What are your thoughts on Co-Parenting Apps?

I gave my fiancé an ultimatum. His ex wife is constantly begging him for money, that has nothing to do with their children. She goes out of her way and comes up with these false sob stories. My fiancé is a very good hearted nice person. He falls for it every time. She has taken advantage of him throughout their entire marriage, and still does. The last time she took it too far. She lied to him about being domestically abused so that he would send her money. This pissed me off, because I am a woman who has actually experienced domestic violence. I told him this was the last straw for me. I told him he needs to change his number. And inform her that they would only be speaking through a co-parenting app moving forward. I also told him if she declined, to file a petition to have it ordered by a judge. He initiated the conversation with her about the co-parenting app and told her she must stop asking him for money. She responded extremely immaturely. She immediately cursed him out about me, and said “their children will never live with me.” And how he would have to leave me, if he wants full custody of his children. She then insinuated that he touched her daughter during their marriage, after he brought up the co-parenting app. Which triggered me as well, because I was actually sexually assaulted as a child. I don’t believe her one bit. If my fiancé touched her daughter, why would she continue to share news about her daughter with him after their divorce. Why would she have not put him in jail period? She is just jealous because he upgraded with me. I am younger and look far more better than her. I am also stopping him sending her money, which is pissing her off. I am his first serious relationship since their divorce. It’s clear she’s just trying to be messy and do anything to sabotage our relationship. I however will not let that happen.

Updates
9 mo
The children currently live with my fiancés parents full time and only see the mother on weekends. This has been the arrangement since their divorce. In their divorce papers it states they have joint shared custody of both children, but states she has primary physical custody. However, the courts have no idea the children have been living with my finances parents all these years. They live a very fortunate life with his paren
Updates
9 mo
They live a very fortunate life with his parents. They have acres of land and both children even have their own horse. They are currently on vacation with the grandparents traveling across the US for the ENTIRE three months of summer. My fiancé is active duty military, and wants nothing more than to have his children back when he retires. What can my fiancé do to protect him and his children?
What are your thoughts on Co-Parenting Apps?
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