Well, there is a problem with just leaving, if you have kids together. I'm sure he must have had visitation rights, and in some divorces you cannot take your children out of state without the other parent's permission. So if she had just left the state, and kept his kids from him, she could have been in trouble.
I realize he has been jailed for DV in the past, but they can't keep a guy locked up forever, once he's served his time in jail, they have to release him. Don't know the full story here, but I presume he wasn't always violent or she wouldn't have married him. There is a daughter, too, I think.
I wonder what caused him to snap? Maybe the idea of her moving to Houston, or her remarrying? Maybe the threat of his kids being taken away from him? Who knows, but I'm sure there is more to the story than what we know right now.