If you really believed that you deserve better, then you would have it.
Work on you, not them.
Keep the focus on you when you look back to sort through your personal history in a bad relationship... whether it was romantic, a friendship, or even work related.
The details are not even as important as how you felt, what your beliefs were that allowed those things to happen.
If your self-worth was damaged, then don't damage it further by blaming yourself for not seeing it.
Instead, realize... that you were worth more then, and you are worth more now. It is up to you to rebuild your damaged self-worth, and to realize that nothing was lost if a lesson was gained.
This will change the course of your future.
To learn more about relationship patterns and how to improve them, check out Doe's book: