This is all just my conjecture, you understand. I don't actually know what's happening. Be careful about placing any authority in what I say.
I would not say that repeating himself makes him desperate. Repeating a dubious assertion is commonly something people do when they're unsure. It's reassuring to them. It's the same behavior as the "affirmations" that pop psychologists tell people to do--you know, "I'm good enough, I'm smart enough, and doggone it, people like me." Repeat it to yourself enough and you start to believe it.
He's telling himself over and over that he's going to be happy if he can just stick it out and get as far as the divorce. He's struggling just like you are, just not in the same ways, and he needs to tell himself that the struggle will be worth it in the end.
IF this is true (and again, this is just a WAG from somebody who doesn't know you!) then he's not saying it to hurt you. He's saying it even though it hurts you because he needs to hear it said again.
