Shut the phone off.

Simple solution.

He needs to tell her to knock that mess off, in no uncertain terms. And why is a 3yo up at 10 pm?

Actually 3 issues are going on:
1) Phone calls after 9pm (any call before 9am or after 9pm should be for emergency only my mom taught me and I've met many who had the same feelings!)
2) Why is a 3 year old up at 10pm?
3) Why does a 3 year old have such easy access to the phone to call?

Seriously needs to be addressed, BM should have the baby in bed before 10pm, and if she can't master that then when he asks to call after 9pm, she should say, "no Daddy is sleeping"

I feel your pain. The lack of sleep (and everything else) because of BM and skids never ends, literally and figuratively. If a 3 year old kid is using the phone, that is his mother's fault. I suspect she is blaming her kid when really she just wants to bother you and make sure she interjects herself into your life. At night she probably thinks about how you and her ex husband are cuddling up or talking or you-know-what, and she (via the kid) probably calls at that time to make sure you don't forget that she was first. BM has been doing that in various ways for 7 years now, not so much phone calls, but making sure she always used her kid to interfere with our plans as a couple. Unfortunately, with a three year old, you will have to force your husband to tell his ex to stop with the calls. There just is no other way. You can't be expected to turn the phone off because some emergency could happen. Things don't get better though as far as sleep goes. When they are young, the needy clingly skids come into your bedroom at all hours with their demands. Then as selfish teens, they keep you up all night playing loud video games and yapping on the phone. And lets not forget those incessant texts at all hours of the day and night from skid demanding money or favors or rides. The only time I sleep is during the week I am out of the house and on vacation without my husband. So sad. Anyway, you should try to deal with the phone issue now or it will escalate. Now it is clearly BMs fault, but latter it will be BM and the kid both bothering you. Soon that kid will be picking up the phone at all hours because he misses his daddy and he has been taught that he is allowed to do this. There need to be firm boundaries. My husband never had any boundaries. I remember on one of our very rare day off from works dates (only one of those every year or so), 9 year old skid called every 20 minutes to talk to dad about how excited he was that it was his cat's birthday. My husband didn't have the balls to tell his kid to stop calling. I could just picture BM in the background, laughing her fat ass of that her kid was ruining our day....less work for her to sabatoge everything herself.

It happened to my DH many years ago. My DH tried and tried and tried to get BM to keep Skid on regular schedule but BM just did whatever please her and continued to keep the kids out late or let them stay up late. And whenever the kids were with DH she shut of her phone and the kids couldn't reach her so they got scared because she threatened to kill herself. And of course they got scared, cried, tantrum, until DH drove them back to check on her at middle of the night to make sure she was fine. Eventually DH learned to ignores her call and checks message instead of answer her right away. And he also talked/explained to Skids what's expected from them and what they have to do...don't count on BM to do the right thing.

A.