Can my ex husband say I can not live with my boyfriend because he does not want his child around him my boyfriend was in jail for asult 2nd degree can my husband do this

Yes or you could just give up custody and then you won't have to worry about it. Why do you want to be with someone like that ?

Yes, he can even take you to court to take the children away.
It will be up to the court to decide if this puts the children at too much risk.

No, your ex husband cannot tell you who you can live with. However, he can file for a change in custody if there is a change in circumstances. The courts may very well decide, especially in these circumstances that have a violent felon living with you would be a danager to the kids and award him custody.

No. You can live with whomever you want but, if you live with someone who may present a danger to the child, this may form a basis for a change of custody depending on what's going on and the details.