Girlfriend left me for her ex. Need a womans point of view

I accidently posted this in the ask a male forum. My now ex girlfriend of 1 year recently left me for her ex boyfriend, they dated 1 1/2 year. There are no kids involved and no voilence. Everyting was going well, the sex was fantasic on both sides,Really. We had open comminucations about it and it never was an issue!
He didn't abuse her but just wasn't there for her she told me numerous times and they fought. I treated her so well and she knows it.
Its been 5 weeks now and I don't want her back.Damage has been done.
Question: Do women usually come back to a man that treated her well if, if and when she sees nothing has changed much now thats shes back with him????
Just curious and want to know what to expect. Is this common?

I had a situation where my ex left me. He was absolutely an awful person.

We were in college at the time and he broke up with me at the end of my junior year. At the end of the summer I came back into town. Funnily enough rumors at work began spreading about how he was interested in me again.

Meantime there was this great guy I had met. I had a few drinks with him and decided an informal hangout. He usually plays frisbree with his dogs in the park I lived by. He said I could come say hi.

Well I know this wasn't a long term relationship, but I got back with my ex. He promised me it would be different. Went through a whole change and work on list, why we love each other, and what went wrong. He promised to keep taking me on dates. Meantime old habits die hard and we slept together.

Did we ever go on the date....NOPE. We did not and I forever felt bad for not meeting up with the nice guy. Some girls like to be treated poorly. It seems like you deserve someone who is better. She probably was not over her ex. Deep down she was never able to let him go. It wasn't you. If I could go back to the nice guy I would have. I would go back to the nicer guy. Just be strong when she does come along. If not, then it wasn't meant to be. Hope this was helpful.