Agree, have run into this issue.
I recently had 2 very happy marriages break up when both wives began heavily flirting with their female friends, they were not exploring or even into same sex so it felt bugged or that something wasn't working. Those households turned on their heads overnight.
I may be misunderstanding the attraction system, but the female sim I'm currently playing is into men. Except all her great or amazing compatability matches are with women. She's openly flirting with women. It's immersion breaking.
@Lenny_Ogg I agree, to me it feels forced.