What's going on here?

I leave home for a couple months, and both my parents start dating. They were divorced, so it's not like they both spontaneously started cheating on each other. But it's been ten years, and it's my dad's first girlfriend in that time, and my mom's had a few short term boyfriends since, and it seems both of them have found someone pretty compatible. I don't want to jump the gun and say that they're both going to work out, but both relationships seem pretty strong.

My dad says he feels guilty about how well he's getting along with his girlfriend. Like, if he could make this work, then he should have been able to make it work with Mom. But I don't think that's necessarily true. Remembering that it's been ten years:
1) When my parents divorced, the issues they'd had were too recent and strong and had very strong emotions attached to them for them to rationally deal with them and work them out.
2) Neither of my parents were mature enough back then to deal with those issues.
3) They didn't respect each other.
4) They didn't realize the importance of communication, nor did they know how to use it.
5) They weren't Christians, and therefore didn't have the value system that is very fundamental. (That the other is a creature of value, that certain behaviors are wrong, etc.)
6) Even after ten years, they're still raw to each other. It doesn't take much to send either of them into a screaming match. The only way they can coexist on the same planet together is by not talking to each other directly.

And I'm impressed by the way both of them are approaching their new relationships. Before they got married, they lived together. Neither thought that it was a big deal. But now, Dad's describing how he and his girlfriend are approaching this as Christians. They do Bible studies together, and they're just letting this develop the way it's meant to. If it seems like they reach a point where it feels wrong to continue this relationship's progress, they'll stop. And my mom tells me that she and her boyfriend are waiting to have sex. They went on a vacation together, and they didn't sleep together. She says when your older and your libido is low, it's possible to do that, and I believe her. I am very proud of both of my parents, and I hope that both of their relationships work out.

Lil' Sparrow