I don't view "we've gotten bad at sex" as evil, though it can be a symptom of "falling out of love." It just depends on the media in question and the story. Plus I can enjoy something even if I don't agree with the protagonist's actions.

Edit: When I say "we've gotten bad at sex" not being evil I mean on part of the person being cheated on not the cheater. Being bad at sex doesn't make you evil and "deserve" to be cheated on.

I don't specifically remember the infidelity in that series, but I do remember the characters. It's very much a "love to hate them" type show like Always Sunny is. Sure, they have genuine moments occasionally but mostly you're just enjoying watching them suffer and get into antics.

I'm not familiar enough with the plot of any Bond media to tell you if it falls in the category I'm okay with. Like if Bond's love interest is also married to the villain and has sex with Bond I would consider that okay. Because the villain is probably abusive.