Divorce Support Forums: CoParenting with a Narcissist

Hi everybody... First of all, please excuse my english bc i am spanish... i will try to write as good as posible...
I had divorced from my 18 years husband a year ago, and after 5 years going forward and reconciliating until nothing can save our marriage. My counselor, from the beggining of the crisis in my marriage, had always said me my ex is narcissist bc his behavior and selfish way of thinking about everything, speciallly our relationship. I can say now he really hit my self steem and still now he continue to do that but now i dont let him or at least i ask him to shut up when he began to attack me, now because my parenting skills.
We both have 3 kids, 8, 15 and 16 years old. And now, my 16 daughter is suffering what i had siffered for many years in other way: a narcissist father. He has a same gf since last december (until then he had had others 3 different gf but never introduce them to my kids in a formal way) and he wants my kids to accept her as a part of the family,letting them to her house (she has two kids), eating all together like a familly, inviting her to a travel he had planned with my kids on summer, although he introduce her to my kids on may.
My oldest Daughter is receiving the hard part bc she is the only one who talks sincerely to his father... my other daughter is 8, too little to talk or understand, and my son try to be appart, not looking for troubles also he had demanded him more attention some times. The thing is oldest daughter doesnt speak at all to his father right now, she said she feel frustrated bc his behavior, she told me she doesnt recognize his father... this bc she had had two hard fights with him always bc his gf. He called me many times asking me for help... crying like a victim bc he loves her daughter, etc, i had helped him,they reconciliate, talk, and then he again began to act in a selfish way, without thinking a little in her adolescent daughter heart. So i asked him to maintain me appart and that he will have to resolve his relation problem with my daughter alone... I had helped him although he always began conversations telling me "you are doing a lot of hurt to your kids"... afforttunately right now i am a lot stronger and i dont accept this kind of games with my self steem... i am a 20 points mother... my children always count on me, they are always in first place for me so... he can say anything just to feel better himself, but he knows that not true... My daughter doesnt want to go to that travel... she prefered to lose knowing new countries, buyng clothes, just bc she is so angry with his father... i let her to counselor, but the last date the counselor said she is so closed, angry and she doesnt wants to apologyze him... she say she doesnt beleive in his words any more... This is so difficult, i can feel her really sad, depress, bc i know she loves her dad. Each time i try to talk to her about apologyzing him or trying to get better and that accepting his father gf is a time set, she get even moro angry with me... Right now the other 2 kids are in dad home bc he arrived from a travel (with the gf and the two kids of her. My children doesnt know this).
My oldest daughter is here, with me, and he is acting like she really doesnt exist although i have to accept he try to call her from the travel and she didnt want to talk with him... In the past years i was the one who dissapoint my ex bc telling him not to spend too much in travels, to think in buying a home, and all of that... now is my daughter who is telling him "hey, please... we need more time with you, i need for more attention from you" and bc this doesnt fit with his plans, he is yelling her each time... This is so difficult... i cant detach finally from him... i can cut the rope from him bc all this issues with my children.. my little D is suffering a lot when he let her to his gf home, bc the daughter of her treat my little children bad!! About my son, he is so difficult bc he doesnt like to talk at all... he try to avoid all the conversations, he try not to see any mistake in him or in me...
So, yes... divorcing a narcissist is a roller coaster still... as when we were marriage and i was trying to get on with our relationship... now is harder bc i live with my kids and i suffer with them their deceptions, their scare, theis frustration...