Liberty, I had a similar situation when I moved here 14 years ago. My x got a Chesapeake Bay Retreiver for my children. When I moved to Calvert with the my children, my x didn't want the dog anymore, so he asked me to take him. Bailey, was beautiful and sweet, but one day a man came to survey some trees for lumber. Bailey was outside, and made a beeline for the guy and bit him in the knee. We were lucky he didn't sue our butts off! My x had failed to tell me that Bailey was already on probabtion in Mont. Cty. for knipping/biting at an off duty LEO that was jogging in a park. Thanks alot, idiot x husband. The next day, after the man was bitten in the knee, we took Bailey to the shelter. One of the hardest things I have ever had to do, but it was the right thing to do. My husband wouldn't take Bailey back, and I knew what his fate would be because he was labeled as a biter. I feel for you and my heart breaks for you with the decision you might have to make. Just thought sharing my story would help you; it sometimes helps to know others have been in your shoes.
Edit: I have thought about your situation more. Wouldn't your x consider taking the dog if he knows you have been injured, and also could accidentally hurt yours/his child, because of his energy? My x has a stone cold heart because he is an alien robot not from planet Earth. I suppose you have already talked with him, and it really isn't any of my business. Your situation is just on my mind.