Charles and Lucie Darnay from A Tale of Two Cities are devoted to each other, having two children during the events of the book (one of whom dies in infancy) and one in the future foreseen by Sydney Carton (after whom the child will be named). Lucie remains loyal to Charles despite his family having caused her father's long imprisonment, and after he is put on trial and sentenced to death upon his return to France, she follows him in a bid to have him freed. Seeing how happy they are together is what motivates Sydney Carton to take Charles' place for his execution.
Joe and Biddy from Great Expectations find true happiness with each other when Pip turns his back on both of them for different reasons (Joe because he reminds him of the humble origins he wants to rise above, Biddy because she is not Estella), and by the book's final chapter they have two children together (one named for Pip) for whom they are both adoring parents.
J. R. R. Tolkien seems to have had a very strong conviction that this was how relationships are supposed to work out, and so his works provied a lot of examples. Almost all requited love in The Lord of the Rings and The Silmarillion ends in happy marriages: Aragorn and Arwen, Faramir and Éowyn, Sam and Rosie, Celeborn and Galadriel, Beren and Lúthien, Idril and Tuor, Bombadil and Goldberry, etc. etc. There is one couple that does not marry (Andreth and Aegnor) and the three that end up unhappily married (Ar-Pharazôn and Tar-Míriel, Fëanor and Nerdanel, Túrin and Niënor) are that way because Pharazôn is evil, Fëanor heads that way, and Túrin and Niënor are cursed.
The number of happy relationships are probably due to the fact that Tolkien himself was Happily Married.
It's worth noting that the story of Túrin and Niënor explicitly states that their curses were part of the most heinous act of the source of all evil in the universe, and even then, they manage to be quite happy for a while, before the curse catches up with them.
Jane Austen: She managed to create a handful of happy marriages. It seems like she puts in at least one stable couple in each book, if only to serve as a subconscious suggestion to her assorted heroines. Her heroines end up Happily Married themselves with whichever men they wind up marrying. It is the trademark of Jane Austen's 'verse and somewhat of a Foregone Conclusion for her novels.
Admiral Croft and his wife Sophia from Persuasion absolutely adore each other. They cannot bear to be separated and spend most of their time being together. Mrs Croft is one tough lady who used to sail with her husband on his ships, and she's a sensible and independent woman; the Admiral has a unique sense of humour, which saves them from falling into Sickening Sweethearts.
Mary and Charles Musgrove from Persuasion. They sometimes bicker and Charles could have been happier had he married someone more intelligent and less whiny, but the readers are assured that they can pass for a happy couple with flying colours.
The Westons in Emma. Miss Anne Taylor, Emma's former governess is a gentle and intelligent woman, and she marries Mr Weston at the beginning of the novel. Mr Weston has never been unhappy in his life, but his Second Love has truly brought him bliss. Their baby girl is born at the end of the novel.
Emma: Mr John Knightley and his wife Isabella, Emma's sister. They have five children and live comfortably in London. She adores her family and is blind to all their faults. He loves her wife, too, and enjoys quiet and domestic life more than anything, though he sometimes sneers at her for being too anxious about everybody's health and less intelligent than him.
The Gardiners in Pride and Prejudice, Elizabeth's aunt and uncle. They are both sensible and affectionate, and they have four lovely children. They sometimes act as parental substitutes for the Bennet girls.
Elinor and Marianne's parents the Dashwoods in Sense and Sensibility until the father's death, and it's suggested that he was also happily married to his first wife, their half-brother John's mother. Mr Dashwood took an exemplary care of his family, and his wife and daughters loved him. They were all taking care of Mr Dashwood's uncle.
John Dashwood from Sense and Sensibility seems to be extremely happy with his wife Fanny; she's a Jerk Ass to almost everyone else, but he nevertheless loves her to bits and thinks her perfectly lovely. To Fanny's credit, she does treat John well and she dotes on their small son.
Sir Thomas and Lady Bertram from Mansfield Park, even though Lady is somewhat of a stupid Lazy Bum and Sir Thomas is highly intelligent. But she's a beauty, affectionate and kind in a very passive way, and he can deal with her very well and actually cares about her. He manages to guide her in important issues, and they are never shown to be dissatisfied with each other.
Perhaps to balance out the many difficulties in their lives, many characters live this trope in the Deryni works:
Rhys and Evaine Thuryn are depicted as an affectionate couple and arcane partners throughout The Legends of Camber trilogy and in the short story "Healer's Song". Their Deryni powers add additional levels to their flirtations and marital bliss.
Lady Alyce de Corwyn and Sir Kenneth Morgan in In the King's Service and Childe Morgan, until her Death by Childbirth. Despite King Donal's sustained efforts to keep Kenneth occupied with business early in their marriage, Kenneth manages to get back to Alyce so they conceive their son Alaric, and Kenneth tells his king this is the reason for it. While Kenneth lacks Alyce's powers, she nevertheless enters his mind for deep communication with him from time to time.
Nigel Haldane and his wife Meraude. In The Quest for Saint Camber, Meraude speaks of being in love with Nigel since she saw him receive his knightly accolade some twenty years previously, and in King Kelson's Bride Nigel says of her, "...once I set eyes on Meraude, there were no other contenders, so far as I was concerned." After Nigel is reconciled to his granddaughter (Conall's illegitimate daughter Conalline Amelia), the two go into Meraude's private apartments, and Jehana describes them thus: "They looked like a pair of newlyweds." Their marriage also follows the Babies Ever After trope; in addition to their three sons and a daughter, Meraude tells Jehana she thinks she's pregnant again in King Kelson's Bride.
Alaric Morgan and Richenda of Marley settle into this after a tense start to their marriage (Richenda is the widow of a traitor, and since she has a son by her first husband, some of Morgan's household don't fully trust her until after she's provided Morgan with a male heir of his own). Like Rhys and Evaine, they become arcane partners (with Richenda filling in the gaps in Morgan's education), and their marital intimacies are also enhanced by their powers. Perhaps because his duties separate them from time to time, Morgan is fairly open about expressing his desire to be with his wife.
Jehana describes the "laughing, happy court" of Prince Létald (the Hort of Orsal and Prince of Tralia) and his wife Princess Husniyya (known as Niyya). Theirs most definitely includes a case of Babies Ever After: in addition to Cyric, Rezza Elisabet, Rogan, twins Marcel and Marcelline, Aynbeth and Oswin, Niyya is expecting another set of twins in King Kelson's Bride. Jehana's mention of them is a bit of a sore point for Kelson thanks to her expressed wish for grandchildren from her only son and his Cartwright Curse.
Kelson and Araxie aspire to this once they decide to marry, and they are determined to build on the friendship and affection that they had for each other as children. Their Official Kiss is the first hint of their success, and the scene at their nuptual bed (which closes King Kelson's Bride) also bodes well.
While they were still alive, Harry's parents Lily and James counted. James pulled a You Shall Not Pass on Voldemort to buy time for Lilly to escape with their son. Pictures of them show them being affectionate and not 'posed for the picture' either because wizard pictures have animated figures.
Molly and Arthur Weasley have seven children, and are always portrayed as having built a solid, stable, and very loving home life for them. They provide such a loving, stable, family atmosphere that they become a de facto adoptive family for Harry when he comes to visit.
Bill and Fleur. The fact that the latter was not turned off by the former's werewolf scars convinced Molly they could be Happily Married.
Vernon and Petunia, whatever else you can say about them, are content in their marriage.
Mr. and Mrs. Longbottom were likely this until they were driven insane by the Cruciatus Curse
Mr. and Mrs. Granger appear to be this, even though we don't see much of them.
Harry and Ginny and Ron and Hermione end up as happy marriages, too.
Word of God has that Luna, Neville, George, Percy, and Dudley all had this as well.
Lupin and Tonks had a short marriage, but it was mostly happy.
Thursday Next and Landen Parke-Laine (although Landen suffers from a case of Ret Gone-induced existence failure for a while, until Thursday rescues him).
In a story-within-a-story that Thursday visits in The Well of Lost Plots, the lead character Jack Spratt laments that as a fictional detective he isn't allowed to have a stable relationship for plot reasons. Thursday advises him to Screw Destiny and live his own life, and sure enough when the novel The Big Over-Easy was published we found Jack happily married with several kids.
In the short story "The Wedding Present" by Neil Gaiman, due to a mysterious magic letter received as a wedding present, Belinda and Gordon have a very happy and successful marriage. In the alternate universe that the letter describes... not so much. Though in the end, after Gordon dies in an accident that doesn't occur in the alternative universe, Belinda burns the letter as she's willing to sacrifice her happy family life for an estranged one just to be able to see and talk to Gordon again.
Edward "Ned" Stark and Catelyn Tully . An Arranged Marriage forged for political reasons, the two grow into deep love and affection, though Ned's rather more reserved about it than Catelyn. In fact, theirs is the only marriage in the series that doesn't directly lead to bloodshed in some way. Probably.Shame what happens to them (though it's a nice way to cram in another trope.).
Amusingly Roose Bolton, of all people, married Fat Walda Frey early in the series (on the basis that she was the best choice given that he was offered "his bride's weight in silver" as a dowry) completely without event and to the apparent contentment of both.
Beauty: A Retelling of Beauty and the Beast gives us Hope and Gervain. The ending implies that Grace and Robbie, Beauty and her Beast, and the girls' father and Melinda will be this too. Beauty also notes that her parents, while her mother was alive, had an extremely happy marriage.
Aral and Cordelia Vorkosigan in Lois McMaster Bujold's books have a rock-solid relationship, managing to combine the best of their two wildly different cultural backgrounds. Witness this conversation from A Civil Campaign, where Cordelia, her best friends the Koudelkas (Kou and Drou, who are also Happily Married), and the relevant parties are discussing the romance between (and possible marriage of) her son Mark and their daughter Kareen.
Kareen: Not... not yet, anyway. It's like I've just started to find myself, to figure out who I really am, to grow. I don't want to stop.
Cordelia: Is that how you see marriage? As the end and abolition of yourself?
Kareen: It is for some people. Why else do all the stories end when the Count's daughter gets married? Hasn't that ever struck you as a bit sinister? I mean, have you ever read a folk tale where the Princess's mother gets to do anything but die young? I've never been able to figure out if that's supposed to be a warning, or an instruction.
Drou: You grow in different ways, afterward. Not like a fairy tale. Happily ever after doesn't cover it.
Hamish and Emily Alexander and later Honor too from the Honor Harrington series. After sixty years of marriage, Emily's injury and whatever else they're still quite lovey-dovey around each other. It also helps that Emily is Hamish's chief political advisor and confidant, so they know how to work together too.
Aivars and Sinead Terekhov, from the Saganami Island sub-series — though she rarely appears onscreen, she is often in Aivars' thoughts and regularly gives him strength to do what he must despite being light-years away.
Honor's parents, Alfred and Allison Harrington. The short story "Beauty and the Beast" shows how (and why) they got that way.
Benjamin Mayhew and his two wives, Katherine and Elaine, who provide a model of how Grayson polygyny works. Katherine, his senior wife, is the more outgoing, politically-minded type, which makes her the official hostess and general First Lady of Grayson. This suits quieter, more soft-spoken Elaine perfectly.
Queen Elizabeth III and her consort, Justin Zyrr-Winton, who is a rock for his wife throughout her turbulent early reign and, later, the first and second Havenite wars. This takes center stage in the short story "Queen's Gambit".
Eloise Pritchart and Javier Giscard, in fact if not in name, on the Havenite side; despite first having to hide from State Sec and then being separated for months on end as Javier served on the front lines while Eloise remained in Nouveau Paris, their relationship is rock-solid from when it begins in the backstory until Javier is tragically killed at the Battle of Lovat. Eloise hides her intense grief and carries on, but never stops mourning him.
Eve Dallas and Roarke. They become more stable after marrying. Roarke winds up going (mostly) legit to avoid upsetting Eve, he tempers her tendencies, and each provides the other with understanding and support in dealing with their respective traumatic backgrounds.
The Drs. Murry. Mrs. Murry remained faithful to her husband for the five years he was vanished without a single word as to where he'd gone, with any man in town ready to throw himself at her.
Following her parents' example, Meg Murry and her husband, Calvin O'Keefe. Their marriage is stable, as noted by characters in later books, but it's more realistic than the Drs. Murray. Meg assists Calvin in his work as a marine biologist, but feels "restless" as her children grow older and are less dependent on her. She toys with the idea of going back to school. Her teenage insecurities come back when she wonders if the rumors of Calvin having relationships with female colleagues might be true.
Jane marries Edward Rochester by the end of the book. She's his care-taker, and she's the only one who can be that to him because their natures suit each other perfectly, and he wouldn't want anybody else's meddling. Both are passionate and intelligent. They have children together, and also Rochester's ward Adele is a valid member of their family.
Jane the narrator says that her cousins Diana and Mary Rivers ended up Happily Married, Diana to a Captain of the Navy and Mary to a clergyman. They visit themselves frequently and all are very happy, and occasionally treated by letters from their brother/cousin St. John from India.
Michael and Charity Carpenter from The Dresden Files. Very happily and solidly married and given that their oldest child is eighteen and their youngest (of seven) is two or three, they have a full married life. In their case, it helps that Michael Carpenter is in some ways quite literally as close to being an ideal Man (in the very best sense of that word) that it is possible to be in a Fallen race and world. He is the best person in Harry Dresden's world, and the marriage of Michael and Charity exemplifies what marriage is meant to be. Charity is not as good being good as her husband but she's getting there.
Papa and Mama Bear of The Berenstain Bears, which makes sense since the authors of the books were happily married to each other.
The Mists of Avalon has Morgause and King Lot. Interesting because they aren't in love at all. Theirs was a political marriage when Morgause was 14 and Lot was around 30, and they regularly cheat on each other (although both of them know about the other's affairs). But they are still very close and when Lot dies towards the end of the book, Morgause spends a lot of time mourning for her 'husband and best friend'. It's actually the best marriage in the book, which is curious because of Morgause's being evil.
Claire and Jamie Fraser in the Outlander series, despite 200 years and a hell of a lot of conflict.
Nuala Anne McGrail and her loving "spear-carrier" husband Dermot Michael Coyne from Andrew M. Greeley's novels. The first three, "Irish Gold", "Irish Lace" and "Irish Whiskey" covered their courtship, and there were a couple of moments where the relationship was threatened(usually by one or the other's sense of unworthiness), but from "Irish Mist" on, it's been pretty much smooth sailing, despite assorted conventional pitfalls (Homeland Security tried to have the Irish-born Nuala deported for no good reason, their third child was born premature, etc.). Not to mention that Nuala's a bit fey, leading to her and Dermot investigating crimes both in the past and the present. In "Irish Gold" the story involves uncovering who killed IRA founder Michael Collins.
The relationship of Perrin and Faile is a bizarre variant of The Masochism Tango. It lessens later in the books, and they claim they are a happy couple.
Lan and Nynaeve's love is a strange variant of The Masochism Tango. Though this significantly lessens in later books and the relationship become more affectionate. In-universe, the couple insist that they're this trope.
Twilight All couples seem to be very happy: Carlisle/Esme, Rosalie/Emmet, Alice/Jasper, Sam/Emily, Renee/Phil. The Canon Pairing: Bella/Edward had shown to be very happy the few months they were married in the books and where not in danger of dying. After the conclusion, a return to this is a given. It's also implied that Charlie and Sue are going to become this.
Jonathan and Mina Harker from Dracula, especially once that whole vampire business is taken care of and they get their Babies Ever After ending
John Paul and Theresa Wiggin, parents of Ender, were most definitely this, despite—nay, because of—their religious differences; just being religious (him Catholic, her Mormon) gave them enough in common to smooth out problems, apparently. To be sure, they have their problems, but how could it be any other way when your children are, respectively, the future savior well, not really, but whatever and the future ruler of humanity? Both Ender and Valentine end up in the same situation (Valentine with kids).
Amelia Peabody and her husband Radcliffe Emerson, archeologist detectives. They quarrel all the time, partly for the fun of it, but also hold each other in something like awe and devote a considerable part of their considerable will-powers to making the marriage work.
Their son Walter "Ramses" Emerson apparently learned from his parents' example and has this relationship with his wife Nefret.
Emerson's brother Walter, whom Ramses was named after, has a very happy marriage with his wife Evelyn. Despite a rough patch after their sixth & youngest child dies.
Eric Flint has a number of Happily Married couples in the Belisarius Series. Justinan and Theodora in the latter, however, are an odd variant. They are not a happy couple per se, but they love each other deeply and are obviously meant for each other. They would probably be closer to A Shared Suffering. That is their unhappiness comes not from each other but from their reaction to The Chains of Commanding, and they are among the few things that make each other less unhappy.
Flint has a fair few in 1632 and its various sequels:
Jeff and Gretchen Higgins. Boy Meets Girl, boy protects girl from army, boy helps girl kill her rapist, boy asks girl to marry him using a bilingual dictionary, marriage is a roaring success.
Mike Stearns and Rebecca Abrabanel. Boy meets girl, boy and girl fall in love, boy and girl become the best political minds of the age, marriage is a roaring success.
Dr. James Nichols and Melissa Mailey, who are husband and wife in everything but name — and quite surprised to discover love at their age. Man meets woman, man finds woman very interesting (and also attractive), woman finds man very attractive (and also interesting), romance ensues. Non-marriage is a roaring success.
Ruy Sanchez de Casador y Ortiz and Sharon Nichols. Boy (or rather man) meets woman, man finds woman very attractive, woman is not interested, man is very persuasive, woman grieves her killed-in-battle fiancé properly, man proposes, marriage is a roaring success.
Howl and Sophie from the sequels to Howl's Moving Castle. They bicker and argue a lot, but that's because they want to. It helps keep them on their toes.
Popular trope in Betsy-Tacy. All of the married couples seem very happy, with a lot of discussion in later books being about how these loving, healthy marriages form and continue to work.
Leonard and Griselda Clement from Murder At The Vicarage. That's despite the fact that Leonard did just about the opposite of what he considered conventionally right when he married Griselda.
Mr. and Mrs. Everdeen. When he died she became so grief stricken she couldn't even look after their children for a long time.
It's never mentioned explicitly that they got married, Katniss and Peeta spend the rest of their lives together in a loving relationship and eventually start a family.
In A Brother's Price, the marriage between Jerin's father and his mothers. The Whistlers are more progressive about their men than most women in this world, and Tullen was good at preventing jealousy. Unfortunately, he's dead by the time the book starts, but at least he left Mother Eldest with Someone to Remember Him By.
What little we hear of grandfather Alannon's marriage to Jerin's grandmothers seems to have been happy. It started with a kidnapping, but Alannon's wives did everything in their power to give him a happy life and he apparently found the situation quite acceptable.
Trapped on Draconica: Gothon and Sophia seemed happy together before she got sick. In truth, he hated her for never providing him with an heir, struck her during a fight, and deluded himself into thinking they were happy while devoting the rest of his life to saving her from an illness he cooked up yet genuinely believes. Then Sophia's ghost appears as he dies, kisses him, and they depart to the afterlife truly happy.
Rana and Fin have jointly ruled Baalaria for ten years and supported each other all the while. There's this sweet little pillow-talk style scene when they're re-introduced. Also, whenever Fin, a formerly The Dragon for an Eviloverlord, wants to convince someone that he's not evil, he points to his loving wife. Third, they're a nice foil for Daniar/Kalak, who are having marital trouble at the time.
King Rhuddlum and Queen Teleria of the isle of Mona have a good relationship in The Castle of Llyr, as do Llonio and his wife in Taran Wanderer.
The extra book The Foundling and Other Tales of Prydain indicate that Eilonwy's ill-fated parents were quite happy together.
Taran and Eilonwy are happily married at the very end of the series.
In Courtship Rite, the maran-Kaiel are a happily married fivesome, looking to add a sixth to make their marriage perfect. They admit that the odds were against them—Noe was a spoiled brat when she married the brothers, and Teenae was simply too immature and got married for all the wrong reasons, but once they figured out their best roles in the marriage, the whole thing ended up working out beautifully.
Song at Dawn: Averted. No one in this story is in love with their spouse. The only exception would be John who claims to have loved his late wife which is why his marriage to Estela is in name only. He married her as a favor to their mutual patron, Emerganda. He didn't even consumate the union. The Court of Love goes further and decrees that marriage is nothing more than 'bodily duties' and one should never confuse a 'spouse' with a 'lover'.
The Kingdom and the Crown has David ben Joseph and his wife Deborah, their eldest son Ephraim and his wife Rachel, and later their other son Simeon who marries Miriam, and his best friend Yehuda who marries Livia.
The Southern Sisters Mysteries have three couples like this: Patricia Anne and Fred have been married 40 years by the time the books start, and eventually two other couples get married and become this: Haley and Philip, and Henry and Debbie.
In Poul Anderson's "Time Lag", Elva was happily married to Karlavi, and happily returning to him after carrying out the duty of the circuit, when the attack that kills him and captures her comes. In the ending, she is told that her son did survive, and that her grandson is named for her husband.
In Mistborn, Vin and Elend are a happily married Battle Couple who are realistically shown to love each other while still getting on each other's nerves every once in a while, all while taking on a God of Evil.
Claudia's parents face no marriage problems throughout the series and treat each other with respect and love, both with similar scholarly interests and jobs.
Jessi's parents are happily married, with three children. They faced slight problems when, as a black family, they first moved to an extremely white town and were ostracized. It was mentioned that Jessi's mother wanted to leave, but stayed out of love for her husband and an understanding that his job transfer was important to him.
Mallory's parents are presented as happily married, with a family of eight children. Both are a Friend to All Children, and enjoy having such a large family.
Most marriages in Wody Głębokie jak Niebo are either arranged or forced and ultimately unhappy. There are a few notable exceptions: Duilio and Sirocco (despite the fact that he tried to kill her); Severo and Arachne (also despite the fact that she tried to killed him several times). It's later revealed, however, that Severo forced Arachne to remain by his side as a demon-controlled puppet. He did it to save her, but she still had no say in it.
Simona Ahrnstedt have very few couples, who are happy together when the story starts. One of the few exceptions is Johan's parents in "Överenskommelser", who are obviously devoted to each other. Gabriel's sister Amelie in "De skandalösa" also seems to be happy with her husband, even if he always seems to have duties somewhere else. In the end though, both the alpha couples and the beta couples will have become happy.
Orrec's parents, Canoc and Melle, in Gifts. Even though Canoc went to kidnap a wife from her lowland town, she volunteered because of her family's restrictive views on women, and found Canoc to be a kind husband. Both of them truly love each other, and Canoc is utterly devastated when she dies.
Orrec and Gry in the two subsequent books, particularly Voices. They've been traveling together for almost twenty years and each is unwilling to let the other face danger alone, but with a great deal of mutual respect.