Heartbroken

Your ex will not be able to keep up being nice forever if he is as abusive as you say he is. That will be when your kids have their light bulb moment.
I'd be inclined to put in writing to your children that you are sorry that they cannot see their way to giving you their blessing but you will always be there for them if they ever need you. Tell them how much you love them and their children but you feel that after being unhappy for a very long time, you feel that you can't allow yourself to be manipulated any longer and deserve the happiness that every body else takes for granted.
To be blunt, it sounds like your children have learned some manipulative behaviour from your ex. They don't have to agree with your actions but to exclude you from family life is just mean.

He won't be able to keep up the loving step dad forever. He is doing this to get back at you and for no other reason. Have patience and your children will see through him Sending love and peace x

I echo BradfordLass's advice. I'm sure she's right. Well done, Hopeful, you've been very strong. I take my hat off to you.

BradfordLass72, your advice is different to mine but I think you could well be right that the ex will soon show his true colours again, and that the children will not be fooled for long.

Your ex is a Narcissist, there are a lot of them about and they are able to convince people they are the victims.

Time, however, shows them in their true colours and I am hopeful that your childreb will see him in this true light.

You are not in the mess, although clearly it seems that way right now. You have had the strength to get rid of a parasite and start a new life and you should not be persuaded that anything you have done is wrong.
You have been very brave indeed - never lose sight of that fact.

Bide your time, leave your daughters to see for themselves what their "father" is like.

I don't agree that you should try to persuade them of your side right now as he will have primed them with lies, so they are unlikely to believe anything you say.
You could write letters, date them, telling them the truth and how much you love them and the grand children - and just keep them against the day the girls realise what you went through.

I cannot see the grand children tolerating him for long. Children are more perceptive than we realise.

Meanwhile, enjoy your new relationship, you deserve happiness - and let time do the rest.

I would suggest you talk this through with a professional therapist.

I agree with FarNorth spend some time putting things right with your family and talk honestly about the problems with your ex. A new relationship can wait at this stage.

Maybe you could put your new man 'on hold' for a bit while you try to restore your relationship with your DCs & DGCs?
If he is really a nice man, he'll understand.
That doesn't mean getting back with your ex, of course. It would just remove an extra complication for a while.

If you can be on good terms with your family again, you could agree with them that they don't have to meet your new man if they don't want to.

I expect the recent changes, and the revelations about your ex, have been a shock to them.

could it be the fact that you haven't given yourself time between the end of your relationship and the start of a new one? Maybe they're concerned about you and /or the GC getting involved with your new partner and then getting hurt if it doesn't work out

Annie Bach, yes my children new the GC didn't want to be here so I went to their house.

Your children didn’t know their children didn’t want to visit your house because of your ex partner ?

Wow, pretty hard to understand that your children would not see through him.
I would give them some time, and then perhaps try to talk to them individually.