更新1:
Okay so, my now ex-boyfriend and I started talking mid-September. My friend, who I considered close, transferred to my school August. I found out yesterday from my other friend that they kissed and were messing around with each other. I asked him (my boyfriend), if it was true and he said yes but denied it happening while we were dating. This doesn't add up because if she came in August, and we started talking MID-September. How do I go about this? I dont want to fight her but what should I do??