OMG, I am so, so sorry that happened and that your ds had to see it. Assault changes everything. In that regard, I've always made it clear to every partner that it's "One and done." If it happens once, it could happen again. I hope you make the right choice for you and your son. Also wanted to say, ds was 19 months old when I ended my relationship with his father, and it resulted in assault and the police becoming involved. Ds would not go NEAR his father while we were waiting for the police. We had 50/.50 during our custody battle, which lasted for years, and ds would FLIP every time he had to go to dad's - even telling me if he had to go he'd rather go to grandma's. I did get full custody, and even up to 5th grade ds was telling friends that he hated his dad. Like I said, assault changes everything. Be strong!