Hey Jen,
Welcome to the Family. We understand how difficult it is to have a partner with BPD.
You're at the end of your rope, dealing with a husband who is manic and barely sleeping and who disrupts your sleep to complain and yell at you. You are taking care of young children and aren't financially able to leave, and you want to be with your kids.
Though he's going to counseling and says he's trying, you don't see any change. You've told him how unkind his behaviors are, yet he persists and won't give you space. You feel that he focuses all his anger and criticism upon you and you're getting to a place where you feel hopeless about this relationship. You've even considered seeing other people, but you'd prefer to have the kind man you fell in love with back instead of this angry man that you live with.
You're really serious about making some changes in your life, so you're starting counseling next week. That's a wonderful step.
Counseling has really helped keep me sane living with a BPD husband. Also reading and posting here has been incredibly helpful. Take a look at the sidebar on this page if you haven't already. There is a wealth of material to learn and check out "Tools" at top of the page. Once I started learning different ways to communicate with my husband and setting boundaries, our relationship became much easier. Now we seldom have conflicts, so it is indeed possible to turn around very difficult situations like what you're experiencing. It's also very good that your husband is open to therapy. So many pwBPD absolutely refuse to go. It will take time, but hopefully you'll see improvement soon once you learn to change how you respond to his behavior.
Cat