What are your ages?
Do you have children?
Why do you think she's rude to you?
Has he talked about leaving her?
Why is he leaving the state?
I can tell that you want to say something to him, but you have to ask yourself what would it accomplish. If he hasn't said anything to you then he either does not feel that way about you, or he doesn't feel it's the right thing to do. I would have to agree with that, if you care about him, you won't tear him up by having to make a decision between you ans his child, obviously he wants to take care of his child and be there for him. I think the best thing to do, is to continue being friends, at some point in the future it's possible that things can change, he may decide to leave her, or he may decide to tell you how/if he feels. In the meantime, you don't want to be responsible for breaking up his marriage, let it be his choice to leave if thats what he wants to do. I welcome your thoughts, let me know if you want to talk more.