The Church says that you may leave an abusive marriage for the safety of yourself and the children. It requires that you not marry again unless you have obtained an annulment.
Well, I mentioned in a different response that we are not Catholic. So.....
However, I also mentioned that my father stayed in the marriage because he felt divorce was wrong, BUT also because it was his duty to protect us kids to the best of his ability and there was no way the courts in those days would have allowed him custody. Divorce would have been a far greater disaster than the marriage was for us as children - although that was difficult to understand at that time.