To me, it seems more concerning that he didn't bring this up, to you, on his own accord, before you were together for a whole year!

It is a very important detail! I can see how that would shatter trust.

I've known of people, it's taken years to finalize a divorce. I've known of people that went through the steps to divorce, and the former spouse went on to remarry. Not sure how that works.

How long have they been apart? Aside from this lack of disclosure on his part, were things fine between the two of you? He's no longer living with her, right?

What caused his withdrawal?