How can you possibly know how to deal with a person who subconsciously feels they don’t deserve happiness?

In a discussion about revenge sex, Val123 was speculating about the circumstances under which someone might abandon a relationship. She asked, ”what if someone just really doesn’t want [the relationship] badly enough? What if they can discard what they have at the moment with the confidence that “something better” is waiting for them just over the horizon? Even if that confidence is misplaced…”

To which, I added, ”And in addition to that, what if they are depressed and don’t think they deserve happiness?” A few lines later she asked the question in the title.

I happen to be in this situation. When I get depressed, I don’t feel like I deserve happiness. I believe I don’t deserve to be married to my wife. I push her away, hoping she will kick me out. This scares her, and makes her scared that it will happen again if I get depressed again (which she thinks is likely). She doesn’t know how to deal with me when I’m like that. She asked me about it this morning and I had nothing to tell her.

What can she do?