What to do in this situation? (details inside)

I’m not sure how to ask this question, but here goes:
Okay, I’ve known this guy for about a year and a half. We’ve been having a strange relationship: we were friends, then he got a girlfriend and we didn’t talk, then we became friends again and now we’ve been seeing each other romantically.
I think he’s got some pretty serious feelings for me and he wants to spend time with me, but I don’t really feel like spending time with him a lot and I don’t really feel anything for him. But I really like him and I’m wondering if maybe feelings could develop. But it wouldn’t really be fair to lead him on, if I’m never going to feel anything.

I just don’t know if I should give it time or just break it off, and I don’t know how to break it off if I decide to do that. I also think I ‘m going to lose him as a friend if I break it off and it’s going to be weird between us and we can’t avoid each other.

I’m just looking for some advice.