This is a specific circumstance I've seen a few times so it feels worth mentioning.

When a guy and a girl are dating, and the guy has a friend who the girl is attracted to. She gives very subtle indications of interest, being careful not to break the facade of monogamy.

One thing I noticed is that she will try to argue/start shit with their boyfriend. This helps her demonstrate that the relationship is in a state of turmoil, so she is trying to show that she may be potentially single. This is one way of getting inside the new guys head.

First time it happened to me, I was the friend. Then I started dating that same girl (naive blue pill days) and she would do it to my guy friend she liked. Now they're dating (good luck, pal).

I bring this up because it happened recently with another girl who is dating my friend, and she pulled identical shit as the other girl (also giving other IOI'S). So now I'm starting to think that it's not just my crazy ex who did this but it's a popular method among hypergamous women.

I'd like to know if any of you out there have noticed this as well.