Right now the harder your try to hold onto to her the more she is going to try to get away.
What should you do? Continue to make changes and become the man you want to be for yourself. Learn from your mistakes. Read books on relationships, self help, parenting. Reconnect with family, old friends, take up a hobby, exercise.
This is a marathon and not a sprint.
Be the best dad that you can be and keep your focus on yourself and your children.
I promise you that it does get better and you will survive and thrive if you are willing to put the work in.
Me 47 STBXW 44 M ~20 D13 S15 BD mid 17 A Disc. 2 months after BD but evidence found ~2yr OM decade older S Imminent D Soon after