These are what we call the 'YMMV items.' Things that some people find in this work. We call them 'your mileage might vary' because not everyone sees these things in the same way. This starts discussions in the trope lists, a thing we don't want. Please use the discussion page if you'd like to discuss any of these items.
One True Threesome: If you happen to be watching for the first time (or the first time in a while) after having spent any time at all in fandom, it's hard not to wish the answer to "Mike or Dex?" were "Yes."
Values Dissonance: Tracy's father tells her the reason he's cheating on her mother with a younger woman is because she (Tracy) is too much of a willful, frigid bitch. And at the end of the movie, Tracy thanks him for saying it.
Not to mention that nobody brings up Seth's bullshit argument that cheating has nothing to do with the other spouse when everyone thinks Tracy's cheated on George.
Though that might have something to do with the fact that, besides Tracy, no one involved in the earlier conversation is present at the later one! Moreover, the movie seems to be inviting us to parallel the two scenes, and to see both Tracy and her father's indiscretions as the simple product of human weakness.
Still, one has a hard time imagining Seth being as calm about it if Mother Lord had cheated on him.
No one seems particularly bothered by the implication that Dex (while drunk) probably smacked Tracy around a bit while they were married, including Tracy herself.
Especially when the movie opens with Dexter shoving Tracy down onto the floor.
The fact that no one's bothered by it suggests it probably didn't happen. We only know of one act of violence on Dexter's part, and it's unlikely Tracy would have stood for much more.
She's also implied to give as good as she supposedly got.
Besides Seth's bullshit argument that his philandering is Tracy's fault for not being nice enough to him—which, again, is clearly the message the movie is trying to get across—multiple characters keep telling Tracy that she needs to be more soft and feminine and imperfect. More traditionally female, in other words, instead of being so strong and assertive. This is a very anti-feminist movie.