@Itsmebee I have to agree with the consensus, it's your 'D'H you need to get rid of for all the reasons pp have mentioned, so no point in me repeating them.
What I did want to ask, though, is what your upbringing was like? I know you've said you've come from a good background, but on paper so did I. Emotionally however, it wasn't great.
Your story sounds very similar to mine with my ex-DP. I actually made myself ill always trying to do the right thing, be the 'good guy'.
Really, my self esteem was through the floor and that's exactly what yours sounds like.
They are ALL taking the piss out of you. None of them (including your husband) respect you.
You can provide your children with a good life, so do that - by yourself. Get yourself away from this toxic shit show. Work on WHY you think you deserve this sort of treatment.
Your H does not have your back. He is also lying about how bad his ex is or he wouldn't have slept with her. I mean, she is bad if she is harassing you obviously, but your H doesn't seem to think that's a problem. I'm sorry to sound harsh but he does not care about your feelings at all. He is quite happy for you t get abuse and still pay. Turn up at things with the woman he pretends to think is 'vile' but slept with.
How low are you down on his priority list that someone who has supposedly caused him all this heartache, is more important than you? He would risk his life with you and your children to sleep with someone he despises??
Get rid. I did and I then found my backbone and have never let anyone treat me like that since.
As for police, it is against the law to harass someone - there doesn't need to be threats - they've fobbed you off because they're busy and you've accepted it. Speak to your local MP about this.