Obsessing over boyfriend?

I go to college with my boyfriend and I commute back and forth while he lives in a dorm. The love is all there, but I have a hard time when we part ways for the day. When I'm at college we spend every moment we can together. He is my best friend, and also my only friend. He is the only person I know at my college because I commute. When I am gone, he often times wants to hang out with his friends that he made in his dorm. He's so sweet and mostly will stay back to be on the phone with me to do homework together, but I know this isn't fair to him. He does so much to make sure I'm comfortable when I'm there with him, I'm practically moved into his dorm room. I'm just not good with people and prefer for us to be by ourselves. How do I accept the fact that he has other people he wants to hang out with? How do I get rid of this feeling of loneliness when he's gone? He's very polite and stays off of his phone when around other people, so he only texts occasionally. Is there something wrong with me?