Well, welcome to PC. That said, there is a lot in your post. I guess the first obvious question is, are you looking to date a married guy? Are you looking for him to leave his wife? What do you want from him?

Married men can be every bit as flirtatious as women. In my experience, in men, it is often ego-driven. Oh, look at that gorgeous new girl, she thinks I'm hot. See, I still got it. Even if my wife is a bi***, I still got it.

No idea if this is what was going on with him, of course, but having been married a long time (no longer) and having traveled for work, I worked with and met a goodly number of lovely young ladies on the road. It did make me feel good to have their occasional attention. I ended up almost marrying an Australian woman I met under just such circumstances. She was very good for me. She made me feel like my (not nice and then history) wife was wrong about me. That I was desirable. That I could "get" another desirable girl/woman, if need be. So there.

I think you may be reading too much into his motives. I suspect they are more basic. But I could be wrong. If I were you, I would steer clear of him and focus on your work. It sounds like finding men is not a challenge for you, so surely, someone solid should come along at some point. And just btw--why have you chosen to be single for so long? Not judging you--I, too, am single, by choice. Just curious.