Huh. The more you know! I always thought that no matter what, if you wanted Loghain alive then Alistair would leave... just investigated, and the only way you can have both is if you harden Alistair and have him marry Anora. Instead of killing Loghain, "Anora's love for her father will stay Alistair's hand."
Interesting!!
Now we're even since it's because of you I found out about Morrigan's mirror!