My then GF at the time and I were together 5 years, I gave her an engagement ring in the 4th of July (Though the fact she was pregnant was the major reason, when the baby didn't make it shortly thereafter, I was just happy to be with her, regardless. Yeah, I was too young for fatherhood, never carried out after the fact).
In December, her parents were going to go to Hawaii for two weeks and her folks wanted her to watch the house, and I said I would love to. But I obeyed my parents. She told me that as I was 18, I could make whatever decisions I wanted to, and many decisions I did do regardless of my parents say so (see "Pregnant").
When I wouldn't do it (I think it was because my parents saying "No" being the only reason) she broke up with me over the phone. Gave the engagement ring back on December 17th.
Bringing this back up made my head hurt and my chest get heavy.
I can't say I would forget about her, I have strong feelings for her, even though she's married now, I'd do it ALL OVER AGAIN.