Limbo, my H is a terrible communicator too. Although I feel he finally is better at sharing things with me. I think the D and finding my own personal peace, and then just being a very good listener, asking lots of impersonal questions so my H felt comfortable, trying to see the affair and his situation from his perspective, never laying out blame or bringing up the past, giving him the freedom to be wherever he wants to be... has made a big difference.
I don't think this will necessarily keep my H from having an A again or eventually leaving me. That could always happen, that could happen even if I was married to someone else. I just have to take care of me, be a stronger better person, stay positive in spite of the ups and downs and know that regardless of what life brings me I'm going to be okay. Yes, it would hurt to go through it again. But I've made it through before I can do it again. And each time I really learn more.
One thing I've learned... some people are weak or just lost (quite a few actually). And we cannot force strength or character into others. We can only work on our own strength, try to make our own character good, and hope by doing this others will be inspired or recognize where happiness is... or at least isn't.
There is no arriving, ever. It is all a continual becoming.