Help, I don’t know what to do.

So today school just got out and one of my good friends from my physics class texted me asking what I was doing and if I wanted to hang out sometime over the summer mind you he is a boy. My boyfriend got very upset about this and was asking me if I was going to hang out with him but we were going to even do and I told him we would just go get lunch and that was it but he kept telling me that no I wouldn’t do that and I would do something else and I asked him why he didn’t trust me and I don’t know why he’s acting like this I told him I didn’t care if he had friends that were girls and he just doesn’t believe anything I say anymore I don’t know why . I left early from his house because I was crying and I didn’t want to really hear him being mean anymore and he got really upset with me. he told me that if I went to go get lunch with him it would be over and I want to go take a shower to see if it would make me feel better and it didn’t and you told me if I got in the shower without texting him it was going to be over and etc. I just don’t know what to do I’m just really upset and hurt. Am i wrong, Am i just too sensitive? is it wrong for me to just have lunch with him?