I havent read all these posts RR but all i'll add is none of us are perfect. We all get on our moral high horses with stuff like this but never quite admit things about ourselves that aren't quite so moral! lol If only we could all say "i have never done anything to hurt anyone or anything, "
Like you say, you do only fancy him, you've not actually done anything other than have lunch with him. If you do, then thats perhaps another thing but even then, i do believe that on the whole, people only play away when there are problems within their marriage. Its so easy to say, "get out then" , but not quite so easy to do.