Attracted to another man

I was a happily married mother of 2 until I started a new job last year. I became intensely attracted to a work colleague ( it literally came out of no where!) and we became friends. Nothing happened between us and I feel like he flirted with me a little but that’s as far as it went.

I haven’t seen him or talked to him for 4 months as he moved cities. I still cannot get him out of my head. It is possibly even worse since he left as I just have the good parts of him left in my memory. I really really want to sever this infatuation with him but I just don’t know how. I feel like I’ve tried everything. Can anyone relate or have any advice? I just want my old life back!