Should I leave him? Help!

I am a 19 year old sophomore in college. For the past 7 months, I have been with this guy who is a 23 year old. We started out as friends and one night we admitted the attraction that we felt between us and ended up having sex. After that night we started hanging out more ( everyday), getting to know each other better, and just being there for each other. I was always at his place. We would study together and I can now say that I know almost everything about him . About 2 Months later, I told him that I wanted a relationship with him. He told me that he didn’t want that and that he just wanted to be friends. I had a hard time accepting that because we acted like a couple but he didn’t want to take the next step. For summer break I left to go home and we stopped talking for a week. Things were weird but we tarted talking again. He came to visit me and he said that he realized how much he missed me and that he wanted me and only me. Now that we are back on campus, we act like a couple more than ever. He calls me his love, baby, all the pet names, but he can’t tell me he loves me. I helped him find a job, I sleep over his house all the time, he buys me flowers and does thoughtful things, we are just always together and people know that we are something. Even our friends think we are dating. I told him yesterday that I would like to be with him officially and he told me that he doesn’t want to put titles on things and that being in a relationship officially is totally different than what we’re doing now. He also thinks that our age gap is too large. 4 years isn’t large to me but he thinks so. I strongly disagree and I am trying to find a way to cope with this but at the same time I feel like I may have to leave him because we just can’t agree on this. What should I do? Is he taking advantage of me? Does he only like the benefits that I give to him?