My ex has been with his girlfriend for around 7 years. She's a lot older than him (he's 30, she's 50) and she's intensly jealous, she HATES me and is sure I will run off with her precious lover as soon as I get the opportunity (I'd be more likely to turn lesbian).
My two sons go over and stay at their house once a fortnight but she has taken a massive dislike to my eldest son. She says he's moody, cocky, has a superiority complex, is a show off, is a nerd - you name it. Its basically that she's jealous of him IMO, he got into the secondary school she tried to get her own son into (and now tells him its a terrible school and he will get beaten up on his first day there because of his know-it-all attitude) and DS has the same grades as her son (who is 2 years older). DS1 is also VERY close to me which turns her against him even more.
Anyway her treatment of him as got steadily worse over the past few months. She takes his mobile off him so that he can't contact me, rips the piss out of him, tells him horror stories about secondary school and slags me off to him. He HATES going to his father's because of her.
But last week they all went camping. I assured DS it would be ok as it was a neutral setting etc. He reluctantly went and now I feel awfully guilty because she was a complete bitch to him all week.
She refused to let him take his phone so he couldn't contact me at all, she shoved a lollypop down his throat because she thought he'd laughed at her falling over (even though her own son was laughing but that was ok 
, around the campfire she made everyone sausages apart from DS because she "didn't realise" and she took the piss out of him on top of a mountain saying "shame mummy can't text you up here, isn't it?"
Anyway, after the lollypop incident, DS shouted at her "you're lucky I don't hit you back" and she retorted with "yeah, then I'd have you up in court"
WTF??? He's 11. How can you have such hatred for an 11 year old purely down to your own insecurities?? She refused to allow ex to let me know when they'd be back, he was ordered to ignore any texts from me whilst they were away.
DS doesn't want to go but I'm really worried that if I say he can't go, she'll talk ex into going to court for him. She has already been overheard trying to pursuade ex to go for full residency so they get the tax credits and child benefit etc.
I don't know what to do for the best. Ex is shit scared of her so even if I tell him, the message won't get to her.