Eh, "Her Desire" does a shit job of this for the most part because (at least initially) they "straight" sex was all cuck or cheating bullshit. So if you didn't want to see a basic cuck game (or general slutwife game, which are a dine a dozen on F95), you basically got lesbian (which is fine and even preferable to cuck) or nothing.
Since, from at least when the game started, the son was the only "main male character" that was part of the setting, it's fine if he's the main focus for any straight sex. Otherwise you end up with a story whose narrative is:
"Hey, where's mom/landlady?
Oh, she out hooking up with some rando dude and showing how much of a slut she is. She'll probably bring them home eventually and we'll have to implement a "take a number" system for them, or make sure mom takes her STD medicine."
Daughter thinks "Yeah, I wanna be a slut when I grow up too and keep my partner count in the high double digits! Just like mom" lol