Am I overreacting????

cass

Okay you guys so I need some advice I'm not sure if I'm over reacting... so my boyfriend has this girl who he is bestfriend with. He used to go hangout with her a few times and it would bug me because they would stay out late like twice. I had a talk with him let him know I wasn't comfortable with it. So now if he goes out with her he brings his guy bestfriend aswell so it's not just them two. So when they go hangout they'll go eat drive around or go to the park and chill but the girl and his best friend usually get drunk and end up messing around (she is engaged btw to another guy) and now if his best friend wants to hangout she's usually there too so I don't feel comfortable with it especially when they be staying out late at night. Especially knowing she is so quick to cheat on her fiance just just makes me feel uneasy. Am I wrong for feeling this way??