This is a strange situation?

I have a strange situation that I have been scratching my head about. When I started college a couple of years ago I met and befriended a guy who went to school with me. He was a heavy set guy who was at least 7 years older than me. We were not terribly close but would often talk and catch up for a little while. Before he left for college he would sometimes get a little to close for comfort giving me big hugs and keep me updated about personal details in his life. He started dating a girl online who lives in North Carolina while he lives in New York. I've often wondered is it maybe because he is lonely. I don't mind the friendship but sometimes it would unnerve me. A year ago I met the love of my life and am now engaged. The strange situation is that when my friend left for college he of course kept in touch which is fine but he continued giving me full details on the courses he was taking, what time they took place, and the like. I don't mind emails every once in awhile but now he wants me to meet him for lunch because he is on break from college. I told him I don't mind meeting him for lunch and that I didn't feel right about doing that alone because I am engaged. My fiance didn't have any problem with it because he trusts me. He knows I would never do anything. I am the one uncomfortable hanging out with another guy without my fiance being there. To me it just feels improper. My friend suggested me bringing him along to have lunch and catch up. I still feel weird though. What do you think of this situation? Is there more to this guy than just friendship. I think he is a wonderful person but something just feels off and always has whenever I hang out with him. Does he seem lonely?