AITA for Not enjoying my friend hanging out with a Guy i dated?

I, 22F, dated a Guy, 27M, that i will just call A, a few weeks ago, Hes a really good Guy. It Just wouldnt be working since Hes leaving for Work in Finland in a few months.

Im still cool with him and am actually seeing a friend of his, I'll call him B, all three of us know about the whole Situation, we talked about it collectively and seperately and are all fine with it how it is rn.

Fast Forward to today: Said friend of Mine, 21 F, ist in nursinf school with me. She was late for class today and first thing she told me was, that she was at A's house till 2am Last night and wouldnt Stop talking about how much fun she had. (She's also dating someone else btw for a few months now)

They met 1½ weeks ago, when he joined us at a Party and after i got a Migraine he went to another Club with my friend and another friend of us.

Now my question ist: AITA for being pissed (and kinda hurt) for being confronted like that and WIBTAH If i asked her for Not continue seeing him since it makes me uncomfortable?

Side Note: A and I Had a real rough Dating time, we both have our mental packages, i am in therapy and he is not which Made it all Just really messy to the Point that he said that he doesnt want to continue seeing me and that B would be much better for me. A and I laughed and cried together about everything possible and i am still really confused about my Feelings which A and B both know about.