Being a single parent isn't the easiest, yet, you aren't alone. I've been divorced for 4.5 years. All boys, 11,9,7.
My ex is a functioning alcoholic. It's something inside him, that he drives at. Workaholic supersedes I believe of him. There's much more to my own saga.
I'm rebuilding my own career path, as I was an at home mom, when it was time to divorce. My sons are developing an appreciation, as my oldest, tonight mentioned how there's similarities in little things between myself and his friends mom, who is also a single mom.
It's a different experience, and not easy, but parenting isn't easy, anyways.
In my state, working or not, there's a $50/month display of showing one is attempting to provide for their kids. Might be something, to consider, getting enforced support.