I wonder if you've rushed into this relationship rather quickly. I know you said it was convenient to have one home. As a Christian, do you really think God wants you living with a man even though you are engaged. If you really want to work things out then why not take some form of marriage preparation course to see where you are heading and to find out what you need to sort out between you. Something like
FOCCUS or
Prepare sound suitable to your circumstances. You can find those programmes in Europe and USA.
If the violence is persistent then you really need to sort that issue out first not only for yourself but also for the children. You should consider asking him to leave until he has sorted out his problems. If you need some support then is there someone at church who can help you?
You can still forgive his behaviour but that doesn't mean staying in a situation where it may happen again.
Kate