Quoting Miss-Maia's Mommy:" Im 20. But I'm doing everything I have to for our daughter. I tried leaving him before and I was miserably ... [snip!] ... and I don't feel completely hopeless. I posted this hoping to listen to others problems and maybe joke about loser dads. lol"
DS has a loser as sperm donor who basically is exactly as your described your bf. Guess what. I wasn't stupid enough to stay with him because it kept me "sane" Because truly. You're miserable with him otherwise you wouldn't bitch about it. You will get over the depression of being without him. You don't need a loser to be happy. You're 20. Time to independent and strong for your kids.
You really want your children to see you in such a horrible relationship? And then one day end up in the same situation because they saw mommy do it and that's normal to them. Sad.