I'm so sorry you are going through this. I came to a point where I felt I couldn't bear to live through another relapse. Giving up hope felt soul shattering. It really felt like a death of sorts and I went through a grieving process. When I gave up hope that he would stay sober is when I was able to stop "helping" him.
I remember an addiction counselor telling me you will know in your gut when you are done and it will become easier and easier to detach.
I hope your kids enjoy the snow. We are melting in my corner of the world.