Crazy messed up feeling......

I am happily married. I have been with my amazing man for going on 3 years. We are trying for a family and have my absolute dream house. We have started working together and there is this guy who flirts with me constantly. He comes out of his way to flirt. He is also married. While I know it's wrong, we never have acted on anything. we've never said anything inappropriate or traded numbers. We aren't even Facebook friends. Any flirting that happens is about something work related. I know it's bad but he makes me smile and laugh and brings back the feelings that I had when I first met my husband. I couldn't ever imagine being with anyone but my husband. I don't ever fantasize about anyone but my husband. I am truly happy with our relationship. I guess it's the attention I crave. My husband doesn't flirt with me anymore. I can't avoid this man because we work in the same department and have the exact same shift. What do you ladies suggest? How do I stop this? I don't want to do anything that will wreck what I have worked so hard for??