hey, b2m ~ I know exactly what you mean. I really miss my guy too. Glimpses of him occasionally, but my H doesn't let him out too often these days. The mean, angry guy you're describing is familiar too - but if we aren't awful, how can they possibly justify their behaviour? Because on some level they feel badly about their choices - and especially when their guilt-inducing spouse is around, I think - they need to be angry at us, so they can feel they are right.
It's hard to take the selfishness and the apparent inability to see the impact of their choices on their children, especially. How to trust them again? I have no idea. I've ordered a book called (I think) Healing the Hurt in your Marriage, which I'm hoping has some suggestions for that.
I don't have any advice, since I'm having a pretty crappy morning myself. Just wanted to let you know that you're not alone and none of this means that you are not a good person.