Boyfriend's Study Group

So my boyfriend has this math study group that consists of another guy a girl and him. He meets with them quite a bit on campus, usually in the library, which is more like a lounge, while I'm at home. My classes are later than his so we never really run in to each other. We live together and have been together for 8 years. We've been through a lot already and I already kind of have trust issues because of him and things from the past and even though I try to let them go I always still have something in the back of my mind that is always stressing about him. So anyway the girl in his group needed something for another classes that they don't even have together and my boyfriend just so happened to have it. So after their class last week he over heard her talking and mentioned to her that he had it. She had a class and so he went to his car grabbed said item and then went to go deliver it to her class. He told me he said she was just a classmate and I didn't need to worry. He's also a person that wants to help everyone that he sees needs help. This week this girl is now his friend. They met up today in the library just them two because supposedly the other guy flaked on them. I decided to come to class a little early and drop in on them in the library. They were in there studying for like 2 hours before I got there and I decided to watch a little before I made myself known. They were sitting pretty close and sharing a computer. So today is also the day they decided to exchange the info apparently about how he has a gf and she has a bf. I guess she asked.. I am open about my feelings and always tell him when I'm bothered. Today he said he was annoyed because I showed up to chaperone his study date and that I'm being controlling and paranoid.. My question is... am I being jealous and paranoid or are there red flags here?