When I was still married legally but no longer together with my wife, I certainly didn't feel the need to go around telling everyone I dated about my failed marriage. However, in a relationship for over a year? It certainly seems like it should have come up. I was in a relationship for about 2 months before I told her. A year is certainly excessive.

On the other hand, if he is not on the way to getting a divorce from his wife, then it's a little different than my situation I guess. I'm not sure what he could be thinking if he still intends to be married to her. That does seem like outright deceit in that case.

What I'm saying, though, is I think you are a little hung up on technical details of whether or not he is legally married. What is more important is why he didn't tell you and what he intends to do about the marriage. If he is not in a relationship of any kind with his legal wife, I would indeed consider him single. Although, if your eventual intention with him is to get married, you need to make sure he intends to divorce her. I also agree that it is somewhat troubling that he didn't tell you for over a year. I understand him thinking that it's just not that important for you to know when the relationship is not that serious but a year is serious...