So i was seeing this girl for a couple months before we got together.(Started around beginning of June)

At first I didnt really feel anything for her and she was always the one that wanted a relationship first. We often just met had sex,etc and next day she was gone. We went „officially“ together around mid october.

Now I found out about something because some guy texted her. I asked her who it was and long story short I checked her chats with him and they had something while clubbing beginning of September and then about 1/2 weeks also while clubbing before we got together.(just kissing)

It was before we went together but I am still pissed... she told me it was because we were just hooking up and was pissed at me etc.

He is also lower smv and looks much worse than me, they havent been texting at all since around the time we went together.

Should I be pisser or al I overreacting?