This is stemming from the inappropriate attention your ex was showing your daughter. You are still in the fierce 'protection mode'. All your senses are on 'high alert', in your efforts to keep her safe. Being that you were a child as well, suggests that you may be feeling overwhelmed, or incapable of protecting her without help. Because you were both 'slaves' of a sort, suggests you feel you have no recourse, or options open to you. That you must deal with what happened.
Is she at an age where dating is a possibility?
Could she have mentioned a school dance, or a boy she is fond of?

Whether or not these types of dreams continue, I would suggest you talk to a counselor of sorts to help you out. Also, I would surely be pressing charges against your ex, if you haven't already. You have the right to protect your child. Don't worry about how he will feel. He obviously didn't care about how you or your daughter felt. The law is on your side!

Hugs, hope, and luck,
J