Sounds to me like he's got his cake and is eating it too. And speaking from a guys point of view, it could just be that you are something he's using to help him get over the wife. An ego booster of sorts until he can move on. But not knowing him, I really can't say for sure.

If it was me, I would use caution.

Someone once told me to "Watch the feet". The feet take the body where it wants to go. So if he really wants to be with you, and a part of your life, that's the way he'll move. Any other way, in a reasonable time frame, and I'd be gone.

Best of luck though.