I think he is just being friendly. Guys do check out other girls but that doesn't mean his intentions are for a relationship. In the long run. He's married, and probably just enjoys his job, and is social, and a fun person. If he is looking for something more I don't believe he would risk his"job" or social status for a fling. Does he like you? I think as a friend he maybe interested in you. He likes to make small talk, and hang out. Maybe the question is. Are you interested in him? If you two are innocently flirting there is nothing wrong with it as long as you are aware that he is in a committed relationship. He did make vows to love, honour, and cherish his wife.
I hope his intentions are just for friendship because I wouldnt want to see you get hurt or humiliated. I once knew this man who was a manager of a bank. He was married, and he had an affair with a coworker. She ended up feeling humiliated, and shunned by the other workers there so she had to leave her job because she was so stressed out. He eventually left his marriage, and continued his flirtatious ways, and affairs with other women in the bank he worked at. The women had to get a new job in another town!!
I hope that all goes well!