I think those feelings are normal. I still wonder about my first love. I haven't seen him or any of his family in years, but I think of him occasionally, and wonder how he is. I found out after we broke up that he's gay, so I don't wonder about a wife or girlfriend. I know he has a SO and that's probably a different experience than wondering about a wife or girlfriend. I don't know that I could explain that, but I do feel like I would feel more "jealous" at the thought of him being with another woman.
I do sometimes think of contacting him. We were great friends for the longest, friends longer than boyfriend/girlfriend. But I never have. And at this point it just seems like it would be pointless. I doubt we have a lot in common anymore, just memories, and they are better left in the past.