As you begin to analyze the story you realize along with strength she gained standards. It wasn't the five year relationship or the one that snuck in between that one..it was the last relationship she would have, the one that only lasted a few months. She found a man that had respect for not only himself but also for her. He proved that he was willing to stick by her and anything she was going through. It was no doubt they started at a difficult time, but maybe it wasn't the wrong time. You as the reader know that in her life everything happened for a reason because all the mess brought her to closure. Everyone in her life though knew he was different and told her how idiotic it was to break up with him. She was scared though and wasn't used to the ' I know you're having a bad day so I sent you your favorite flowers' or 'I'd rather spend every moment I have with you than anyone else', so she ran. She was never treated right, until him. He set a standard for her that would last a lifetime. He made her realize that a man can love her the way she always wanted. Letting someone know how you are upfront does make the worlds difference and he taught her that too. He told her that she had the capability to light up someone's world... and one day she will again. In time he made her realize everything she was capable of in every aspect.
So in the end she realized she could let men in, she just had to know the good from the bad... and it was the 'one who got away' that would teach her all of this. She'd be forever grateful because now she could move onto the second book.