My one HUMBUG with this Enchanting film - (don't think it's possible to write a real spoiler???)

Rating: 10/10 (2 December 2007)

Okay, okay, the world LOVES Enchanted for 95% perfectly good reasons. So did I hence my '10' rating. However, even excellent films can be bugged. Given that one must tread very lightly when applying 'real' values to a Disney Fairy Tale my Hum Bug is, I think, never the less valid.
Many laud the 'lesson' the movie teaches young girls to wit: Even a man who seems to be a Prince Charming may not be the right man for you.
Now, if that is a LESSON then here goes lesson #2 that no one mentions:
Expect your true love to DUMP YOU for a woman he's met and known for a day or two and despite: 1) You've been a devoted girl friend/fiancé for FIVE YEARS
2)You've been faithful for five years
3)You are very smart,sophisticated, educated and savvy.
4) You are understanding, not pushing him into marriage given his history of a wife who walked out on her husband and child.
5) You dismiss your jealousy when you find a beautiful girl in his apartment because you TRUST him.
6) Even at the end, at the ball, you hope against hope that he will not betray your five year relationship.
7) You are simply stated a very NICE GIRL in all the right ways.
8) Finally, you are so depressed, all your hopes and dreams having been dashed, that you resign from the human race and take the first opportunity to jump off a roof....NO I mean jump down a man hole.
Why can't the writers simply have Dempsey dating his girl friend for several months instead of FIVE YEARS which is so absurd. OR use the tried and true film technique of the UNSYMPATHETIC girl friend???
Have any of the writers seen like Sound of Music or the all time favorite, The Parent Trap? In the latter Dennis Quaid's 10+ hottie girl friend is not only 100% deliciously evil but is also shallow, a gold digger, secretly hated his kid, was 1000% materialistic and was forever scheming for her self interest. She was a girlfriend all loved to hate, So that her day of reckoning was hilarious and welcomed by all. Such comedic writing was a high point of those and other similar comedies. WHY NOT HERE?