It's funny. In my game, Alistair ended up saying that he might as well be king, because he didn't want Anora on the throne (this would be after her second betrayal - which, by the way, was awesome). I kind of boggled at that. He also decides to suddenly take the throne if he thinks you're going to spare Loghain. I think that speaks more to his relative immaturity than anything else. He still has a lot of growing up to do, apparently.

And I liked it that he broke up with you. Finally, a romance option that isn't for granted. And it was for a good reason, too! And then you can get back at him by making him sleep with Morrigan. (I agree with you - that would be some epic hate sex.)

The best outcome, IIRC, is if Anora marries Alistair. She's the politician, he's the man of the people, or something like that. I liked Anora - she frustrated me with her constant double-crossing, but she did what was necessary for her to retain power. I can respect that, haha.