A PFA or Protection From Abuse order is an order from a judge that declares that he shall be arrested if he comes within such and such distance of you. I don't know the ins and outs but your L does and I know there is a temporary PFA that you can get immediately without waiting for a hearing or whatever. Hands around the neck sounds like a threat to your safety. That's abuse in my book. Physical abuse and threat of physical abuse is illegal and unacceptable behavior in ANY RELATIONSHIP. I hate to think of this guy being free to come to your 'new' home and taking your kids to care for them. Then who does he throttle?
He needs help. And he won't ask for it directly. The only way he will accept it is if he has motivation. I think the law will help you give him that motivation. Your life and the life of your children and the lives of anyone who depends on you and the lives of anyone who depends on him will be affected if not threatened by his unaddressed unacceptable behavior.
Don't your kids deserve to be raised by their own living mother?