My answer is that they shouldn't. Duncan being the douche he's only loved Courtney for her looks in tdi. But at tda it was revealed that he loved a lot lebih about her. And Courtney was commonly confused of love. Like most people are.
Here I can explain why I have no problem with them trying to change each other: Courtney wanting to change Duncan because she wanted him to be a better person. And I have no idea why Duncan did that too. Courtney was trying to make Duncan a better person just as Duncan was trying to do to her. Both never had a problem with the list. In fact when Duncan came back oleh speculated about how it went. He see,ed quiet happy that she took the time and effort to try to make him a better. Person why he wanted her out of the game is because she kept annoying him. Is where he got mad at her and where he betrayed her. So I don't see the problem both wanted the best for each other. Sure the writers did this awful but at lest it was passable in my opinion. And Gwen fan please don't try to start a debat about this subject. It wouldn't be fun I'll a sure you.
The biggest problem I had with these couple is the didn't get along which I explained a lot of stuff in this article:
link. About how I feel about the couple.