samels001 I'm sorry, you ask the same questions I did (still do now but less). the good news is that it's entirely to be expected and it does get better.
I don't know why your XH did that rather than just be honest. But I wouldn't assume he's happy just because he makes a show of it, I'd bet it's bravado to cover his discomfort with what he's done.
All I can say is ask yourself if it helps you to go over and over it and ask yourself these questions. He just lied to you and chances are you'd get more lies if you asked him why instead of trying to work it out alone. Something I've had to accept is that I could have ended our marriage earlier than I did, god knows I had enough reason to but I didn't. Before I get into another relationship I will need to look at myself carefully and understand why I stayed so long despite what I knew.
I reckon it was less about love and more about loads of other stuff, not least such a long time with the same person. If you've followed my threads you'll see I get myself into a real pickle sometimes but someone always comes along and strokes me or kicks me up the bum whichever is necessary.
I'm biased of course, but I don't think marriages which end in the way yours has can do the clean break thing - it was messy before it ended because he was lying to you and you didn't know it, however, the mess is out in the open now. At least you know and can deal with it, painful though it is.
Is there light at the end of the tunnel? there has to be. And if anyone deserves it, you do. 