I've never been in a romantic relationship so this is only conjecture, but I'm pretty sure not everyone would react the same way you did. Some people would loathe your ex, some would just get depressed, others would probably have very conflicted feelings like you did.
It was made perfectly clear that she knew what AZ did was horribly wrong and left him because of it. I also wouldn't take other canons into account because there are written by different people and tend to butt heads with each other already.
Plot convenience and Rule of Drama.
Touché. And while I realize that canons often contradict each other, if things are consistent between them, then I'd say they are pretty much secure regardless of other contradictions.
And I never said Floette didn't understand what AZ did was wrong. I just said she understood the reason behind it and she decided to make AZ learn his lesson. Of course, Floette as a species tend to be very forgiving motherly Pokemon as far as I can tell. *shrug*