Why are most of our BM's complete nightmares?

DH has been trying to get BM to stick to email contact only. Sometimes she will and others she won't and even when she does she's usually trying to trash DH or start a fight with him via email. There's always some sort of accusation that the kids said this or that to her. And if DH doesn't get to the email soon enough or doesn't want to answer it here comes the texts. I mean heaven forbit DH be to busy to check his email or just doesn't want to respond to. Nope. It's fight time.

DH typically ignores it but I've gotten the point where I'm done with it. All of her crazy behavior over the last four years has pushed me to the point where I just wish she would drop dead. Sometimes what she says gets to DH and he gets all p!ssy and it ruins our evening or day depending on what time satan decided it was time for attack.

DH sent her an email Monday which stated that he's asked her repeatedly to stop badmouthing him in front of the children and due to the fact that she won't that he'll address it with kids and let them know that what their mother has stated is not true and will no longer be addressing it with her.

The email also stated that he has also repeatedly asked her to stick to email contact only which she has also refused to do. From here on out she is to email all child related issues, requests, or questions to him. Texting is for a scheduling emergency that cannot be addressed through email due to time issues, and phone calls are for emergencies only e.g. hostpital or car accident. If she can't follow these simple requests that he will be getting a land line and will provide her with that number so that she can call and leave voice messages and he will block her from the use of his cell phone. He said that he is tired of her always trying to pick fights, her aggressive and angry outbursts, and that he will no longer allow her to try and ruin his time. He also told her that she needs to focus on herself and her family and leave him alone unless it's child related and requires his knowledge or attention and that he felt that this was in the best interest of the kids.

I think that it was pretty straight foward and to the point. Not hostile just this is how it's going to be. You don't like it, well tough. He knows that he has to deal with her because of the kids but he refuses to deal with her being hostile and dealing with her atatcks via text or phone call.

Can DH look bad infront of a judge with an email like this? We have four years of her documented craziness. Everything from sitting outside our house at 3 am, stalking DH for a year, coming into our home without our knowledge an approval, showing up at our house without of knowledge or approval, to addmitting up to badmouthing DH to the kids, messing with visitation, and constant documented attacks via email and text. And there's much much more.