I feel so sorry for Don. He has to be a saint to have dealt with that woman for all of these years. I hope she makes good on her threats and leaves him soon so that he can finally be set free from that devil woman's clutches. Then he'd be able to find a mentally stable partner who would actually respect him and treat him with a shred of dignity.
What I guess I'm trying to say is, if you haven't seen this episode yet, don't bother watching it. It's a waste of an hour of precious life that you'll never get back–ever. You'll be left wishing you'd spent the time differently, much like poor Don does when he thinks about his marriage.