Ex drama and kids, advice please!

Hi all, I apologise now, this is going to be long!

My fiance and I have been together a year now. 4 months before we got together, my partner split with his ex who he has 3 children with (now 11yo, 6yo and 2yo) because she cheated on him. Remember this part - SHE cheated on HIM!!

So, she moves the guy that she cheated on him with, into the home they brought their kids up in, he moves out. They had a verbal agreement on when he saw the kids, and he voluntary transferred money into her account each month for the kids.

As soon as she found out about me, things changed. She demanded that I meet the children (we had only been dating a month if that) she said that if I refused, she would tell the kids about me anyways. So I met the youngest first. That morning, in the early hours, she called him, saying that she couldn't cope with the kids and that he needed to come get them. He got up and dressed, then got a text saying not to bother and to meet at time they had agreed... It gets weirder. So he meets her at the school, to pick up the youngest so she can work (like they did every Friday) and she is all over him, asking for a kiss and a hug, crying, saying how can he just stop his feelings for her, how can he just stop loving her etc. He said he stopped loving her the moment she admitted to him that she had cheated, and left with the little girl. He meets me, and we go for breakfast, thinking how weird she is being.

We have breakfast, and he gets a call from her, saying that she can't cope, she's going to kill herself. He tells her to pull herself together, that the kids need her, and if she feels like that she needs to get help, and he isn't the person to do that. She goes on and on and he cuts her off. All of a sudden, he yells "move!" at me and she bursts into the restaurant, comes charging towards me, picks up my crutches (I'd recently had an op on my leg) and tries to hit me with them, yelling about me not becoming her daughter's new mum and other stuff I don't remember. He stops her from hitting me, she yells at me, snatches the buggy and drags it off, down the stairs to leave the restaurant. I yell at him to go after her. He comes back about half an hour later saying she wants to apologise to me. I said no way, keep her away from me! So I take the elevator and he meets me downstairs - she is there. She comes up to me and says "sorry for throwing plates at you, but don't you dare think you are going to be a mother to my children. He will get you pregnant and trap you. Will be get you into debt. He will cheat on you" Etc etc with her finger in my face. I just nodded, didn't know what to say to her, i didn't Wana make more trouble. She says "look at the state of you, you think you're so smug, you will see" and eventually leaves. Anyways, that evening he gets a message from her mum saying that he needs to have the kids for a week as she is going to get help. If he can't find childcare, he needs to go to social services as she can't help (meaning her mother can't help with childcare) the kids don't hear from her all week. He has to take unpaid leave from work during his probation period meaning that he later looses him job. More on this later.

Another time, my fiance borrowed my car to drive to work and she followed him, called him from the car behind, yelling and swearing at him. He's pulls over to talk to her and the youngest is in the back of the car. He tries to take her out coz he's worried about her driving with her when she's this angry. She kicks and hits him to stop her, so he leaves, she thumps and kicks my car, then gets into her car and speeds up behind him. He stops at a junction and she drives her car into the back of mine! With little one in the car!

There are so many instances like this! He lost his job in January, and so hasn't been able to pay much towards the kids, which, understandably she is upset about. So she stopped him seeing them since Feb. Stopped replying to his emails (police got involved and they were advised to only communicate through email) He got a job in July and still he hasn't seen them. He went round to the house and it looks abandoned. He contacted social services and he got an abusive email from her as they had spoken to her, saying that she was going to let him see them but not anymore. He has been trying to go to mediation but unfortunately he has contacted some terrible companies, he is now on the 3rd company and things are slowly moving. Problem is, he is on 0hrs contract, some weeks he only has 16hrs work, sometimes more, but he is still paying off bills that she has racked up since he left the house, and after child maintenance, he doesn't have enough to pay for mediation. That's why it's taken so long. Now they are just waiting for a date, his dad agreed to help us out.

Anyways, each time he hears from this woman, he is a broken man. She is spiteful, and tells him that the little girl won't even remember him, and that her bf is her father figure. He just wants to see his kids! She just wants money! She sends him childcare bills, that's all the contact he gets for the most part. And remember, he hasn't had a job since January, so HE could have looked after the kids when she was at work, but she has cut off her nose to spite her face!

I just feel awful, like all of this wouldn't have happened if it wasn't for me. I hate seeing him in tears, crying because he hates to think that his kids don't know him, or they think he doesn't care or love them, when actually he never stops thinking of them. I don't know how I can comfort him, or how to deal with this woman! I hate her for everything she has caused, and making him feel this way.

Ladies, any advice on what I can do? How do we deal with this woman! This isn't even half of the story, there is always drama with her. And she's going to have to be in our lives forever! I love this man, he is the most caring, thoughtful, amazing man Ive ever met. How he is with his kids is one of the many reasons I fell in love with him! Thanks to reading this far 💖