In Genealogy of the Holy War, Ethlyn and Quan are a Battle Couple who never argue and support each other in helping Sigurd (who is Ethlyn's brother and Quan's longtime friend). Promotional art shows them and their kids as a loving family.
Selfina and Glade in Thracia 776 are both knights. Selfina reassures Glade when he feels guilty over the deaths of his troops and Glade likewise when Selfina is still mourning the death of her friends Quan and Ethlyn.
Yuno and Zealot in Sword of Seals are another longtime Battle Couple who tried to retire and start a family before getting called back into service. Yuno's sisters both gush over what a good husband Zealot is; in Yuno and Zealot's own supports, they worry about the daughter they left behind but agree that they both need to stay in the field.
In Blazing Sword, Pent and Louise are another couple that joins your army. (Their children both feature in Sword of Seals.) Their supports are basically about how much they love each other and want to be with each other when the war's over. One of the rare non-Battle Couple happy marriages occurs with Dorcas and his NPC wife Nathalie. Her status as an Ill Girl drives Dorcas to banditry, but she follows him to talk him out of it despite her condition.
In Awakening and Fates all married couples fit this trope. Especially notable if the player steps on an event tile and you have a married couple paired-up. The event in question can ranged from them promising each other to survive the war, giving gifts to one another, or commenting how beautiful their spouse looks. That is not even getting into the stats boost granted by married couples.
Firewatch starts off by talking about the relationship between Henry and his wife, Julia. What starts off as a beautiful love story quickly turns sad when Julia develops Alzheimer's within her late thirties.
Kingdom Hearts has (in theory at least) Mickey and Minnie Mouse. Since they rule together as King and Queen, it's not unreasonable to presume they're married, although it's never explicitly stated that they are.
Prior to this they were married with children in Mickey's Christmas Carol, where they played the Cratchits; they also appeared to be married in a dream sequence in Mickey's Nightmare. A particular quote of Walt Disney's from 1933 tends to float around, stating that "In private life Mickey is married to Minnie..." Fans tend to either shrug this off or take it as canon; either way, the main consensus seems to be to keep them eternally courting as to not "spoil the illusion of youth."
Atrus and Katran of Myst, in contrast with their epically screwed up family in general. And if those two had paid more attention to what their kids got up to, the Stranger could have avoided twenty years of troubleshooting.
Saavedro and Tamra count as well (that is, before Sirrus and Achenar arrive on Narayan...) Sadly, it's never clarified if she survived/stayed single in those twenty years when Saavedro was trapped.
Cecil and Rosa of Final Fantasy IV, at least after the credits and in the sequel. The only primary couple in the main Final Fantasy series to date that has managed this, astonishingly. While some other pairs are implied to become this later, Zidane and Garnet of Final Fantasy IX most prominently, only Cecil and Rosa have officially tied the knot, which is what this trope is about.
In Final Fantasy VIII, Cid Kramer and his wife sorceress Edea were a happy, loving, and mutually devoted couple until Ultimecia's possession of Edea forced them to separate. Once they're reunited after the end of the game's second disc their marriage is as strong and supportive as ever, with Edea describing Cid as her knight.
Final Fantasy XII had Ashe and Rassler and their Perfectly Arranged Marriage. They share a joke in the prologue about how everyone thinks they're marrying for political convenience when the reality is they're in love. Since he dies in the opening credits, Ashe becomes a Crusading Widow for the bulk of the game.
Wakka and Lulu from Final Fantasy X. Their marriage is a sign they've moved past their angst from the first game note the death of Wakka's brother and Lulu's former boyfriend and indeed they are happy and parents. One such mission in the sequel is searching for a sphere containing information about Wakka's parents which Wakka is looking for because he wants to use it as a model for what a good father should be.
John and Abigail Marston of Red Dead Redemption. Even though Abigail is held hostage for most of the game, John turns down the advances of many women, and does everything within his power to get his family back. And eventually he does.
Part of the Harvest Moon experience is the player character becoming Happily Married to the bachelor/ette of their choice. Supposed to be a small part of the game, but Popularity Power means that it's grown in importance as the series continues. That aside, within the games themselves are several (dozen) NPC couples, the majority if not the entirety being Happily Married.
Subverted in Harvest Moon DS (Cute) where, when you talk to the rival couples after marriage, all but one couple seem to voice doubts about the marriage to the player.
Umineko is impressive by managing to have two very unexpected Happily Married couples; Eva and Hideyoshi, in a family full of internal squabbling and backbiting, manage to be good, loving spouses. She snaps as soon as he dies, showing that the marriage is really Eva's rock concerning her sanity. And secondly, and doubly impressive is Battler/Beato, counting as a bizarre combination of Happily Married and Unholy Matrimony; Battler is The Hero, and Beatrice is The Chessmaster. Everything suggests that they honestly enjoy challenging each other, though, and it might just be a pillar of their happy marriage.
King's Quest: Graham and Valanice seem to be doing pretty well for themselves, Alexander and Cassima also seem to be doing okay, Cassima's parents seem happy, and it's pretty much assumed that Edgar and Rosella will go here... eventually. In the Fan Remake of King's Quest II: Romancing the Throne Caldaur and Lavidia, Count and Countess of Kolyma also are still quite in love.
In King's Quest (2015), Graham and Valanice are in their dotage but still adore one another. Their children's marriages are also implied to be happy, although neither Edgar nor Cassima are ever seen in the game and Cassima isn't even mentioned by name.
Khalid and Jaheira of Baldur's Gate. Sure, Jaheira is bossy around him but their marriage is a happy one. She also cries when Khalid dies. The player character can also be married with either Jaheira, Aerie and Anomen.
The world of Thedas seems significantly more accepting of extramarital affairs than a normal medieval setting, so the only romantic pairing in Dragon Age: Origins in which the player ends up getting married is with a female Human Noble Warden and Alistair. Theirs is, however, an extremely happy marriage; the epilogue states that Alistair openly adores his wife, much to the delight of the rest of the kingdom.
The Human Noble Warden had an excellent example of a happy marriage in their parents, Bryce and Eleanor Cousland. The origin story depicts them as kindly people who love each other very much, and remain Together in Death to buy their youngest child time to escape. The Warden's older brother, Fergus, is also shown in the origin story as being happily married to his wife Oriana.
Although their mother has died by the time of Origins, the City Elf Warden's parents, Cyrion and Adaia Tabris, are understood to have been very happily married. It's even stated that Duncan wanted to recruit Adaia to the Wardens years earlier, and part of the reason she didn't go was because of this.
In the Awakening expansion, if Nathaniel Howe is recruited to the Wardens, the party can facilitate a reunion between him and his sister Delilah. She's now married to a shopkeeper named Albert, and is quick to assure her brother that she didn't get married out of desperation; in her own words, she adores her husband, and is expecting their first child.
If Hawke assists in the courtship, Beta Couple Aveline and Donnic get married between Acts 2 and 3 in Dragon Age II. Aveline has a personal quest in Act 3, as well as several lines of party banter, which indicate that the marriage is very solid and quite happy. From what little of it is shown in Act 1, Aveline's first marriage to the ill-fated Wesley Vallen was also very loving and happy.
If Hawke is female and romances Sebastian on the friendship path, he will ask if she is willing to enter a chaste marriage with him, taking vows as a Chantry sister. If she accepts, they get married almost immediately; from what is shown of the relationship in the remainder of the game, they are very happy together.
Although Hawke's father Malcolm died some time before the beginning of the game, everything their mother Leandra says about her marriage to him - and everything that Hawke and their siblings remember about it themselves - indicates that it was extremely happy and loving, despite the hardships created by Malcolm and Bethany (and potentially Hawke) being apostate mages.
In Dragon Age: Inquisition, depending on the player's previous choices, Morrigan and the Warden will be married in all but name. They are still very much in love and are completely devoted to one another.
Also in Inquisition, the DLC Trespasser may include a wedding for the female Inquisitor if she romanced either Sera or Cullen and accepts their proposal. In both cases, the epilogue indicates that they are very happy together.
Monkey Island: Guybrush Threepwood and Elaine Marley as of the end of Curse. Despite Elaine's arguably superior intellect and competency, she always trusts Guybrush. The only time their marriage is remotely threatened is in Tales, when she falls under the Pox of Lechuck and he spends his entire adventure with another woman, but he never turns away from Elaine, and by the end of chapter four it's clear that she'll do anything for him.
Tomodachi Life: Miis who are dating could become this; it occurs when one of them wants to propose to the other. To propose, the player has to help the Mii out by alerting them if their partner is thinking of them. If this is done four times successfully, the Miis get married, you'll get to see their wedding, and their honeymoon. Eventually they could have a baby.
This can also occur on child Miis, but the player has to use the Age-o-matic on the couple after the proposal so the wedding can take place.
Almost every Dynasty Warriors and Samurai Warriors husband/wife team is a good match between people who do care about each other, often ignoring both history and the source material, though Hideyoshi is still a bit of a lech and Nohime is a very mentally disturbed woman.
Flint and Hinawa, the parents of the protagonist in MOTHER 3. They're only seen directly interacting with each other once, but between the sweet letter she sends him at the start of the game and the fact that Flint nearly goes insane when she gets killed, it's more than clear that they love each other.
In keeping with the idealistic nature of the setting before the Pigmasks take over, almost every couple in Tazmily village seems to qualify if you pay close attention to their dialogue. Abbey and Abbot, a young couple who appear to be both florists, particularly stand out.
First there's Taupy and his wife/live-in girlfriend Muffy. While she's largely a Satellite Love Interest, it's clear they love each other and that their situation works for them; any time Taupy is home, he and Muffy are shamelessly affectionate.
About halfway through, Kyrie and Morte become an Official Couple. Agan seems to think they're Sickeningly Sweethearts, but he's the Butt-Monkey and The Complainer Is Always Wrong; they're actually less schmoopy than Taupy and Muffy. While they're still teenagers (and thus unmarried), they have none of the drama or jealousy typically associated with teen romance, and the ending implies that they'll continue to stay together.
The Warcraft franchise had a Love Triangle with Malfurion Stormrage and his brother, Illidan Stormrage, with their childhood friend, Tyrande Whisperwind. Even as a Love Triangle, however, all three were on very good terms with each other until Illidan's Start of Darkness. Illidan is eventually exiled (then killed), and Malfurion and Tyrande tie the knot in the novel Stormrage. Their relationship is never portrayed as anything less than True Love, with nary an argument to be seen.note Tyrande, being the night elf racial leader, can be killed by Horde players for an achievement. Despite Malfurion being in the room and doing nothing when Horde players attack reaching memetic status in the forum community, it's an artifact from the days when he was still missing and is for the sake of a fair boss fight, not actual canon.
Battle Couple Lynn and Karl are explicitly stated to have also become this after the war, with the two raising their child together.
Valkyria Chronicles III ends with Kurt and either Riela or Imca becoming this after he proposes to one of them, with epilogues depicting either his and Riela's wedding, or him and Imca running an Orphanage of Love together.
In Strawberry Vinegar, Rie's parents never fight despite seeming like polar opposites sometimes. Her mother does occasionally tease Rie's (easily flustered) father though.
In Guenevere, Guen's marriage to Arthur has the potential for this. If options are chosen that indicate she's happy in the match, he will fully reciprocate, and other characters will remark on their apparent bliss.
In The Elder Scrolls series' backstory, Lost Orphaned Royalty and the future Queen of Morrowind, Barenziah, was the last surviving member of her noble Dunmeri family after Tiber Septim's Imperial Legions sacked Mournhold. Septim's Dunmeri General, Symmachus, convinced Septim to spare the girl as she would prove useful as a Puppet Vassal Queen down the line. After escaping from her Imperial-loyalist foster family and having plenty of adventures in her youth, including spending time as The Artful Dodger and participating in The Oldest Profession, Symmachus tracked her down and sent her to live with Septim himself. After an affair with Septim turned ugly, Barenziah would marry Symmachus and take the throne as Queen of Morrowind. Despite the potential for issues given their history, her marriage to Symmachus turned out to be a very happy one. However, Symmachus was killed during unrest in Morrowind and, fearing for her life and the lives of her children, Barenziah abdicated the throne and fled to the Imperial City. There she met King Eadwyre of Wayrest in High Rock, and the two would enter a marriage of political convenience. Once again, despite the potential for issues inherent is such an arrangement, the marriage was by all accounts a happy one.
Pokémon Sun and Moon has Professor Kukui and Professor Burnet (the same from the Dream Radar application). The anime, however, start them out as a couple with them getting married after the Ultra Beast arc. In both cases, they are quite happy together
Ky and Dizzy in Guilty Gear, while technically not married due to in-universe legal reasons, are for all other intents and purposes a married couple in-between XX and 2 and still refer to each other as husband and wife, making them the first instance of a married couple in a fighting game where both partners are playable.