I am getting ready to finalize paperwork on my divorce. My X and I separated in March. He went through times that he is quite nice with me, other times that he is total crap to me. Still blames me, I just could not care less. Anytime he gets nasty w/me, I tell him there is really no reason to communicate w/me unless it is regarding our children.
Now, he would never send me ten nasty texts on mothers day. I agree, that is abuse. He wanted you to cave, you did not. So, he is doing all he can to make you as miserable as he is. Don't fall for that sort of behavior.
For my situation, as time passes, it has seemed to get a bit better. I think he had to have time to digest what was happening and come to terms with it. He is not ever going to accept that his behavior caused it, but that's on him, not me. My children and I know the truth and that is all that matters to me.
I am putting my focus into being the best I can be for both my children and myself. I deserve that and so do they. I have turned him over to God, what happens in his future is completely out of my hands.
Good Luck and God Bless!