OP, your timeline is really confusing. Is the person you’re now in a relationship with your first ex-husband? If, as you say, the reason for moving there with your baby daughter is so that he can help with your shared son, why do you need to be in a relationship with him?
I honestly don’t understand why you can’t seem to stay single for more than 5 minutes or how you even have time for a relationship with all of this going on. Your daughter isn’t even a year old and you’re already in a new relationship since splitting with her dad. When did you leave him?
I don’t blame you for wanting to move away from this abusive prick, but if that’s what you plan to do, then you should speak to a lawyer and make sure any abuse is documented in case he does try to stop it. Also, don’t tell him anything; you’ll just give him more power to try and mess things up for you.
You might not like to hear it, and some posters might think I’m being cruel, but I honestly can’t understand why after finding out your daughters were sexually abused by your husband, your first thought is to get into another relationship, move them into his house and get pregnant.
I would advise that once you move, you need to seek some counselling, and please do not get into another relationship.