Welcome Norfolk,

I'm sorry you find yourself here.
There is a lot in your post that strikes me, but I'll focus only on one thing.
You have your daughters at home with you. More than anything else, they need you to be there for them now.
I encourage you to focus on the, possibly look at getting them and yourself into some counseling. It sounds to me like you can all use it...especially if you are having suicidal thoughts.
Your wife is going to do what your wife is going to do for her own reasons. You have no control over that and if you do try to control her at this point, you will only push her farther away.
You have more than enough to keep you busy and occupied right now. These things take time. Use this time to get closer with your daughters and work on your own issues. We all have issues.

BOM