To not understand this about ex?

You cannot control other people’s actions, only your own.

Stop worrying about what he’s doing and who he’s spending his time with and focus solely on yourself and your children.

You have a lot of healing and inner work to do. Focus on rebuilding yourself and making a happy and healthy home life for your children whilst they’re in your care. How he chooses to parent when he has them is up to him (unless you had concern or abuse/neglect etc)

Keep your communication with him to a minimum and speak purely about what you need to with regards to timings for the kids etc.

He could stay with this new woman for a life time or they could end in a week and there could be another 100 women in his life but that’s his business and life and nothing for you to lose sleep over or try to understand.

All you can say to him is that if he had prioritised you and the DC the way he is his new woman you would still be together.

You have to learn to detach and remind yourself that it’s not your problem . Even if your ex is one of many that the boy meets, it’s up to his mum to parent like that.

How long ago?

in any event, I think you are probably spending time analysing and feeling hurt and upset and hating this entirely innocent woman because you haven’t made inroads in to building a new life post separation. Plan things, see friends, take up a new hobby, commit to improving… fitness, decorating. Something, anything

He’s angry because you called him out on his behaviour and didn’t stay subservient to him doing exactly as he pleased. You hurt him and his pride and narcissism.

You are hurt because you wanted him to love you in a different way and want to spend time at home with you. So you rightly called time on a failing marriage but that doesn’t mean you instantly stop loving the person you were with for so long.

Hes bounced straight into the arms of someone else because that’s exactly what men like him do. But because he’s a nasty bastard he’s using it to hurt you by comparing you to her unfavourably (which is purely his words not fact don’t forget)

It’s such a mark of a person when they react to not getting their own way by lashing out and being cruel.

OP see this as more evidence of the man he is and be thankful you got out whilst you still have life left to live.

Stop letting him having any power over you. This is NOT a person whose words and opinion are your concern now. Yes of course the years you were married meant something. But he isn’t going to say that to you because he’s angry and a twat. So stop listening to him.

Keep contact civil, brief and only about the kids. Do not pump them for info about the new woman. It’s hard enough for them as it is.

Put all your energy into supporting your kids and finally doing things on your own terms. Hobbies, fitness, travel. Go live your life.

So you don’t need to say you “actually do feel sorry for her”
when you don’t

and why do you hate her? She’s going out with the husband that you saw the light and ended it

this is all a bit odd op

Everyone seems Better in the beginning. Christ I’m better in the beginning but when you get into it and you see my varying characteristics it’s not the same as the person you’d meet because life and circumstance show you who a person is. Can 100% say whoever I’m with I give my all and don’t give up easily so if I’m in, I’m 100% in, ain’t no one got your back like me. Not everyone’s the same as that. Some people get flaky when things get tough. Let it wash over you, water off a ducks back

You don’t feel sorry for the other woman, come on op at least be honest with a group of anonymous posters who don’t know you!

Theyre on holiday and you’re navel gazing about him, when clearly he is a profoundly unpleasant man.

Feel sorry for your own children for having him as a father rather than another woman’s child.

Who told you this?

He has met quite a few men?

A) that is precisely why he is telling you
B) OP you really don’t sound like you’re over him if you’re getting hurt by his words

He moved on so quickly because he can't be alone it's the worst thing you can do .
He will throw his all into this new person to try and get past the hurt of things ending while telling himself he hates you when he really doesnt .
Stay on your own heal ignore his hurt leave him to deal with that while you find you again .
He didn't nurture your relationship he let you feel lonely dont care what he thinks.
Just move on to a brighter future be excited for it.

He's not your partner anymore so his emotions are his own problem

this nails it. He’s so used to getting you to do the shitwork, he can’t even see it. This is just the emotional equivalent of slinging his manky y-fronts in the wash and magically finding them washed dried ironed and folded in his drawer, without ever making the connection that someone else was doing all the work.

Try to get yourself to a point where you can just laugh at what a bloody wet wipe he is.

You "dumped" him and damaged his male ego. He can't blame himself so instead he has to paint you as the bitch from hell. That's what men do - all the time. Not only did you damage his gigantic ego but you also ended a very cosy lifestyle for him. I expect you looked after him like a mother figure whilst he carried on doing whatever be wanted. Nice set-up for him. I bet woman number 2 won't put up with it and he's finding out the hard way.

He’s known you for a long time and will be well aware of how to hurt you whether it’s introducing the kids to new woman quickly or saying that he hates you.
He can hate you but enjoy his new life at the same time. You may have blindsided him because he didn’t think that you would act on your threats (16 years is a long time not to act) or he’s angry that you don’t agree with his perceived right to do what he wants, when he wants. He may be pissed off that his behaviour has been exposed to people who were unaware of his selfish behaviour eg mutual friends or his parents or that you have some free time to do what you want when you didn’t in the past.