IMHO, weight means little to nothing in a relationship that is built on love. My last relationship was with someone who is overweight, I am not skinny (I have a weird body, everything on me is muscular except this rather large gut, but I digress) and it was the best and most frequent sex I ever had. And no, I am not a chubby chaser. Love can just get you anywhere IMO, regardless of body type.

This post here? This obviously isn't based on love, this sounds like a fling where I think body type is probably a lot more important. I'll say this, if you think the guy loves you, he will sleep with you and not care for a second what you look like. It sounds like the love was there in the past from him but you aren't sure if it's there now. Based on what little you said, it sounds like he still has feelings.

I think the real question is.... If this guy has real feelings for you, is it a good idea to have a fling? If I was the guy in this story I'd say no. If it really is "just sex" and you know it's not going to leave this guy wanting more, I say go for it. But if there is ANY hint that he might want to be more than friends and you don't? It wouldn't be fair to him to lead him on.