Given how toxic the relationship has been, per your description, there would be a higher likelihood that he would have cheated on you at some point.
However, there are no guarantees that he did cheat and worrying about that would not help your situation.
He never seemed to care all that much about you or his daughter at the times when he has been out of prison in the past.
Hence, the likelihood of making a motivated effort to look for you and your daughter when he gets out is slim.
He may make a feeble attempt at finding the both of you upon initially getting out, but it is unlikely that this attempt will persist.
Given his nature, he would most likely try to find a new partner to manipulate, with you being absent.
To move forward and let go of your feelings for him, think about what is best for your mental and physical health.
Think about what is best for your daughter.
Think about the past six years and the manipulation and abuse that you have been through.
Now, ask yourself about whether you can handle another six years of that.
How about another twelve years or twenty-four years.
Ask yourself about whether it would be worth it to spend the best years of your life remaining stuck in a situation that you have been unable to change.
These kind of questions make you reflect on today and on what is to come.
They give you perspective.
If you come to understand the hopelessness of what it would mean to stay with this man for many more years, you will find it easier to move forward and allow your feelings for him to start dissipating over time.