Sims excessively flirt with others

yesterday I had an interesting thing happen in game.

One of my sims aged up from teen after she broke up with her girlfriend (who had aged up before her) and then asked to be just friends with her, I then had her marry someone else.

Her husband and ex-girlfriend where at the house at the same time and in a conversation with the wife sim. Husband randomly flirted with ex-girlfriend of his wife (he was flirty...), wife gets upset. Then the husband flirts with his own wife and the ex-girlfriend (who was not in the conversation now, just in the room), gets upset. When I look at the relationship status ex-girlfriend have with the wife it is just Just Friends and broken up, nothing with loving each other or anything. But she is now also angry at the wife for cheating on her. Like what? You have broken up already and are not in love, she has no romance bar with anyone else so it is not the husband she is jealous of.

All of this just because of a flirty mood.

Also, there is something wrong with milestones in my game - I'm going to see if I can find it reported already - but romantic ones does not happen on both sims most if the time. So if a sim fall in love, start a relationship, woohoo, get engaged and then married. Sometimes on of the sims won't get the milestones. Usually they are supernatural, but not always. I noticed this when my alien elder wanted to fall in love/ get married. Like what? You have been married all this time. Come to find out the game did not recognise it in all aspects. He has a spouse in the relationship tab, but they cannot be soulmates or anything because the game does not recognise them as in love/ married. Maybe have something to do with the marriage family tree update

Anyway, wanted to mention it here as well because if sims don't recognise they are married, no wonder they might flirt with others.