Help!

About 8 months ago I separated from my husband of 13yrs. I didn't realize he was a narcissists and bipolar with abandonment issues till we were almost 5yrs together and had kids together. I stayed for so long hoping he will change for the better and tried to give my kids a family as we both grew up in broken families we didn't want that for our kids. The last 4yrs together he started ruining me mentally and verbally but brushed off as he would say that I should be happy and thankful he's with me and not out and about with friends at bars, clubs or just hanging out with them. He was home with us! During the pandemic I caught him texting a coworker and said she was nothing. I didn't believe it! I found out he was doing so many drugs (coke, shrooms and pills) I didn't approve. He would call me all the worst names in the book in front of my kids and in-laws, I just broke and had no one to turn to so I felt trapped with no where to escape. Till one day he came home from the bar and started calling me names again it got physical! That day I said 'Enough is Enough' and walked out. Bought a house moved in and left him with everything! I just wanted out! My kids and I were living alone trying to build our lives. Since I moved out until now he's been begging me to go back and I refuse to do so as I don't deserve that. I deserve better! Now my ex found out I'm starting to date and trying to be happy, he has been putting our kids against me! Now my kids decided to go and try to live with him as they're been brainwashed that it was me that doesn't want or wanted to build a happy family with him! My son disrespects me all the time saying women are nothing (just like he dad used to say), slams doors and punches walls, etc. My ex called cops and child protective services on me saying I'm a bad mother and cops and CPS found no proof of anything!

Please help me figure out how I can get my kids to stop believing anything he says. I need advice and help 😪