Basic Trope: A (usually second or third) wife, who is a status symbol for her wealthy husband.
Straight: Bob was married to Alice, but then when his career took off, he had an affair with another woman named Betty, and eventually left Alice for her. Betty is younger and prettier than Alice, and probably much younger than Bob.
Exaggerated:
Bob actually becomes a Serial Spouse after his career takes off.
Bob's marriage to Alice was unhappy; cheating with Betty was only a symptom (not a cause) of their fighting and eventual divorce. His relationship with Betty brings him happiness, but he isn't marrying her solely for her beauty.
Gender Inverted: Alice was married to Bob, but when her career took off, she had an affair with Charles, and eventually left Bob for him. Charles is younger and more handsome than Bob, and probably much younger than Alice.
Invoked: Bob has been fighting a lot with Alice, because she's unhappy that he's at the office all the time. He meets Betty, and one thing leads to another, and he ends up in an ongoing relationship with her.
Exploited: ???
Defied: Bob feels that this is wrong, and he breaks up with Betty, and starts to put in more work on his relationship with Alice.
Discussed: "Bob left a great woman like Alice for thatBrainless Beauty?!"
Conversed: "And what happens when Betty gets too old?"
Deconstructed: Bob let his success go to his head, and that's why he ended up being unfaithful to (and eventually divorced by) Alice. He may have been unhappy when he was with her, and that led to fighting...and his negative feelings made him vulnerable to Betty's charms. Also, Betty may be young and beautiful now, but eventually she will become older, pudgier, and wrinklier...what then? And it's possible Betty only married Bob for his money...and what if she's a Black Widow?
Reconstructed:
Bob decides that Alice has been there for him through a lot while he was getting his career together, so he focuses on building a stronger relationship with her, and breaking off his illicit relationship with Betty (or turning her down in the first place.)
Played For Laughs: Betty is an absolute Gonk, who also has a repugnant and utterly caustic personality, yet Bob and everyone else reacts to her as if she was the most desirable woman on the whole world.