you have a right to know why your own wife won't talk to you. Too bad if she gets mad when you ask her, if she doesn't want to be with you, she should have the guts to say so, not ignore you and treat you like she's "better than you". You were good enough to marry, what has changed?
If my husband started to act like this, I would get an explanation, I know you may be afraid to find out, but with no communication what kind of marriage do you have?
It's hurting you as you are smoking and drinking, don't do this to yourself.
It's better for kids to be in two separate homes than an unhappy one. If they don't see their parents as loving each other, having fun together, working together, etc. they may have problems with their own adult relationships.
I would demand an answer for this behavior, it's not acceptable.