Tired of being the fall guy as ex tries to pull me down and potentialy damage children. I think there is something seriously wrong with him

My now ex husband lies , manipulates, twists truth, has terrible temper and thinks everyone is against him. He cheated on me yet blames me that i wasnt a good wife. He came and went for three years during seperation always saying that he was sorry or made a mistake and i would fall for it. We have 2 small children together and I come from divorce so I really wanted to believe that he meant it . His actions never followed his words. Promises were always broken  and I would always  find out that "she" the homewrecker was still around. The children and i paid a huge price for this. This woman knew he was married with a 3 yr. old and a 8 month old and got involved anyway. To add insult to injury she was nothing but rude and condescending to me and shows no empathy. We just sold our house 1 month ago and me and my children are living with my brother until I have a plan. I have a son with learning disability so location and school are factor. Although we are divorced almost 2 years most of that time we spent together "trying to work it out" so children saw him almost daily in our home and now their life has changed so dramaticaly. He also has become so hostile toward me and verbally and emotionly abusive. My daughter witnessed  (she 7 and adores him) one of his rages when he showed up day i was moving and he was screamong in street throwing garbage cans and boxspring into street. She was inside but could see. When i tried later to talk to her about it she acted like she didnt know what i was talking about{so strange}  and then eventually she said she was crying because I was yelling at her dad! She always takes it out  on me and blames all on me. She shows or tells me all her frustration and is model kid to him. He has now subjected our kids to outings with this awlful woman.ALREADY! I not only have such contempt for her but i truly believe it is way too soon no matter who it is. They are adjusting to so much!! In addition a couple yrs. ago when i found a hidden second cell phone that she gave him while we were"working it out " my daughter was in the car and accidently it was on speaker as she called and got me. I wasnt thinking clearly and we were having "words". She was yelling at me. I was yelling back. I was shaking and telling her to stop talking so rude that my 4 yr; old could hear screaming. She didnt care. I was crying afterward and my daughter was crying asking me what happened. I told her the womans name but not the reason. Still wrong but i am human. I told  her that angela is a bad person and to never trust her if she ever meets a woman by that name. Three years have passed and i thought she was out of picture. He was back living at home again but........... so now my poor girl met a woman named Angela and is confused. What do I do.The first time he did it was about 1 week before the move and without not nly discussing it with me but I had no clue he was even with her again. "Just ran into to her couple weeks ago" he says .The lies never end. My daughter told me that he met dads "friend" but couldnt remember her name. 2 days passed and i couldnt take it I thought for sure that she must know and was scared to tell me. She never forgot that car experience and through years occassionaly brought it up' I decided to just tell  her the name . I also didnt want her to feel betrayed when she found out on her own. I felt bad to cause her pain because she cried so hard and had a bellyache from it. She said"Dad must not know that she is the girl who hurt you because he would never ne with someone who mde you cry! Heartbreaking!!!! So of coure I sad you are probably right he must not know. I dont wwant her to have bad feelings toward either one of us. I want her to feel safe and loved and worry about kid stuff!!!!!!! She says she never wants to see her again and brings it up often for next couple weks. Lots of questions that i cant or scared to answer. I tell him and he ays that i am puyying negative shit in her head and it is my fault.half stuff he thinks i make up. We agree that it wont happen again or at least for awhile. He gets mad at me for something and next day does it again. To sppite me???? I dont know. I know he loves them. I know him for 18 yrs. Could i have been so wrong???Did he lose his mind????  Her dad tells her it just a friend and mommy has friends that he doesnt like . That it is ok. This woman doesnt deserve my childrens affection. She had no regard for them being a player in the demise of their family and the lose or all security they had. Also how will my kids feel especially my little girl when she or if she discovers the truth. Sometimes I think she knows but is staying quiet. She is pretty smart. Will she feel lied to or betrayed? Feelings that i know hurt like hell, for  me not tellling her the truth or will it be more damaging if she knows. This was my life starting when i was 4. Ultimately my dad left us for another woman and they are now marriied. It was an awlful life and still not easy. I found out alot of thiings on my own. My mother tried to protect us and wanted us to love our dad but the truth does come out. I was just hoping that in my case the other woman would dissappear but shes back!!!!!! She is a constant reminder of what happened. Wish he could meet someone, ANYONE, else. Our childrens lives will be harder than they need to be.Family functions, communions, parties, etc.... I can not just lie down and take it all. I am tired of being disrespected. I will not be called a c**t again by anyone!!!!!!He has no impulse control and is unpredictable , he goes from "im so sorry" to "your nothing but a piece of garbage" in one day. Anyone out there going through anytrhing like this?