Would you be mad at this?

So my bf and I have been together for 5 years. In the beginning of dating we both were leaving for college and going to be long distance. He was on a family vacation and his uncles gf brought her sister’s kids (she has custody of them). Well of course the girl is my bf’s age and going to the same college as him. Long story short he told me that everyone said they were kissing on the beach. At the time I was upset he said that but was like whatever. Then we kept dating and long distance was good and a few years later she got invited to his house for Christmas and I was with my family in another state. H never told me she was there I found out since he liked a picture of her from a year ago in a bikini which barely covered anything. This time I flipped since I did not feel comfortable and felt something was off. His parents also don’t like me and do like this girl and that makes me even more insecure. Well now here we are and he went to a party the other night and she was there and commented on his photo.. which okay fine that’s not his fault so I asked him did he talk to her and he says no. So I wait a few minutes and ask again did he say hi to her... yes he did say hi to her. I’m not mad he was there or that she was there it’s the fact that I asked if he talked and he told me no. Now he’s turning it on me that I am freaking out he said hi to someone which isn’t the case all I wanted to know is if he talked to her. I’m pissed because he always changes the question around when he knew what I was asking. So what do I do now? Currently I dont want to talk to him since he upset me a lot... there’s a few other things this girl has done such as texting him flirty things and all but bottom line is I don’t feel comfortale and he has known this. If he called me and said hey I just want to let you know that she commented on my photo she was there I said hi and that’s it I would have been fine it’s the fact that I had to confront him and he lied to me