No point trying to work out why he is doing what he is doing, it'll drive you crazy.
As you say you can't control the situation & you can only control your own life.
You are a great Mum, the kids rely on you & yes you will be okay as a family - together.
To be honest they wouldn't have a clue what us Mum's do or how we live our family lives & if they were given the chance to have full custody they would probably run a mile after a week because they couldn't handle it.