<human>: Can you summarize the given text in a few sentences?

One of my internet friends has been joking with me for a while within our circle of friends that we are married. It was strictly platonic. He eventually asked to hang out, as we live in the same city. I had a fun time with him, but I'm not attracted to him and I have let him know several times that I'm not looking to date right now. I have let him know that I enjoy this friendship. However, he somehow managed to misinterpret that as potential for a relationship and is now overly affectionate with me. I also find that his lifestyle is extremely not compatible with mine - I am active and goal oriented, in school and working with a busy social life and he still lives with his parents and is unemployed. How do I tell him that nothing will ever happen with us without being harsh? 
I should add that he was earlier trying to do the same thing with my real life friend/his internet friend and she started flat out ignoring him, at which point he started insisting that he was never interested. 
I don't want to be rude as we have many mutual friends and he would probably make me out to be a selfish bitch who lead him on, although I genuinely was not aware that he was going to try to get all romantic on me.
<bot>: obvious joke flirtation turned into friend's genuine romantic desire, don't know how to back out of it without hurting his feelings/looking like an ass