I am new here and while reading through the threads I came upon your story.
I am ever so sorry to here about your situation. This seems like a terrible ordeal.
It isn’t easy being so tethered to an estranged partner. Only made worse financially by the pandemic.
But remember that you were a dedicated father for many years. Money is useful but only a vector for success. You true success was being a committed father. You owned that, so still do when you are with your children. They will remember that forever and NO ONE can ever take THAT away from you.
I know it must be hard for you to be away from them, but perhaps in this time try and device ways to make your life better FOR THEM.
That is your why and if you hold on to it oh so preciously it may be the one thing that helps you get out of the hole you find yourself in.