I haven't posted to you in a long time but I have been keeping up on your thread.
I'm pretty sure that my H was suffering drepression before the affair, and he still is, but he doesn't see it. Anyway, before the bomb I was walking on eggshells because he would go off at me about everything/nothing. Every time I made a comment about something or asked him a question he would contradict me. And he would complain or snipe about things I did saying "you ALWAYS do this" or "you NEVER do that".
I got pretty sick of the petty arguements over nothing every day. So when he would do this instead of taking the bait I would agree with him then change the subject or carry on with something else. I didn't defend myself. Basically I just refused to be drawn. I know this is tough, it's not right and it's not fair but it's probably your best course of action right now. That and choosing your battles? I mean, come on an agruement about chicken?? Sorry, don't mean to be flip. You know what I mean though? Unless I was actually starving I would have just said "actually I'm full up, why don't you have it darling?".
Living with a drepressed person definately is not easy. And yes sometimes after a doctor has diagnosed it people do act as if they have an excuse to be rude and arguementative for a bit. I know this because I have suffered in the past and did exactly that. Try and read a bit about depression if you have not already - I think Amazon have some good ones on living with a depressed partner. How about reading the Chapter in DR on depression again?