I agree with those who say, woman is looking for security, emotional, financial, etc. But this girl got already engaged with other man. It means this man has met her requirements in terms of security. But when she knew that security of her 'old flame' could be higher, she changed her mind.
And since we are also talking about emotional security, 4 years ago our guy could give much more stable emotional security to the girl than now. As at that time he was truly in love with her, and all he wanted in his life was her. She ignored this emotional security. Now this area isn't safe at all, as obviously too many girls are after that now-a-rich guy lately, it is hard to talk about any type of emotional security now.
Areta_NZ, i didn't say all 4 years she was engaged to other man. I said, that during these 4 years she has met another guy, got engaged and eventually broke up.