frustrated & hurt

I can't believe the bullshit I fall for. Valentines was our 24 yr anniversary. I had no desire to celebrate a marriage that was ending. Three days before the soon to be x told me he bought tickets to a concert and couldn't get a refund. He doesn't have anyone else to go with and doesn't want to waste them. I told him no way was I doing anything with him. He has this unreal way of guilting me into whatever. I told him it was not a "date" or for him to have any idea that this meant I was reconciling. We have 5 kids together so maintaining some kind of a mutual relationship I believe is important. So I reluctantly agreed to use the day to start working as friends ( not spouses). Well the very next day he tried to kiss me in front of the kids, so when I refused he then went off the wall about how Im using him. I treat him like a tool.  Im a real piece of shit! My kids are so very angry at me and he just keeps feeding their resentment for me by creating these scenarios. My children want nothing to do with me and are all making plans to move out with him. This entire thing is so out of control, I don't know how to turn it around. I don't want my kids to come back to me one day and ask why I didn't fight for them. So right now Im fighting for 5 teenagers who keep telling me to go die. When will this end?