I would say this: DBing is not about saving the marriage, it's about making you a better person.
I agree totally with this. I look at DBing as being instruction on how to live your life, how you treat people in ALL your relationships, and how you view yourself. It's about how happiness is something that you are always working towards, that it's something that belongs to you and you alone.
It's also an effective way to survive the extreme pain that we're all in, by forcing ourselves to be proactive about things instead of falling into full-on depression. Making little steps that eventually lead--surprise!--to happiness and a full life.
HC, I think you should keep DBing even if preventing divorce isn't your goal. And this board can help you navigate your friendship with H, keep you on target. I know that it keeps me on track, knowing that I post all my missteps and flubs here. Posters want me to succeed, for me, and not necessarily to save my M. The people here have the most amazing outlook on live and love as I have ever encountered, and I trust them to help me. And reading other people's similar experiences helps me feel not so alone.
It is in the shelter of each other that people live.--Irish proverb