Coworker wants to have affair with me - advice needed
A couple of weeks ago, a coworker of mine asked me if I would have an affair with him. This blew me away. I did not quite know what to say but said something like - I don't do that. He explained his reasoning - likes me, finds me attractive, just wants to have some fun. It was very awkward. He apologized afterwards and asked that I keep this to myself, which I have til now. The following week we went to lunch (we had made plans previously) and I took this opportunity to talk with him about his proposal and why it was wrong. I thought we both were at a comfort level where this would not affect our relationship and ability to work together.
While we work in different programs, they do overlap and we do have to work together. I am a manager, he is not. It is a small office, so I see him every workday. Since our discussion, I can tell he is trying hard not to cross the line with me but he continues to make comments about how attracted he is to me and wishes we could get together. I have asked him politely to drop it and move on.
Any advice on how to manage this situation. I do not want any coworkers to know, including his supervisor and my boss. I just want to keep this to ourselves, but the comments need to stop.