You're wondering why he doesn't want a divorce.

I'll tell you.

There is nothing better in the world than convincing a little piece on the side that you'd love to be with her forever, but you can't because of your kids or because your wife is sick or because she'll bankrupt you with alimony. The best blowjobs I've ever gotten were from women who bought that shit.

I don't know any guy, catholic or not, who didn't manage to get a divorce if that's what he really wanted.

So the next time he tells you that its you he really wants to be with, secretly tape him. Then send the tape to his wife. It'll move things along a bit.