Hey Beautiful Sissi, good for you for coming back to SR and posting but I have to second everything that everyone has said.
Could you get yourself to an Alanon meeting? It does look like you need more support. Knowing that all the promises are BS is a good start but staying away from someone like this is super, super difficult.
We all get it; we all have our human drug AKA addicted loved one. It is really really hard to say no and make it stick. Being friends with our qualifier is a bit like a drug addict doing drugs in moderation. Even if you have to drop out of school and move away to get away from this guy, do it. (I say this as a teacher who thinks education is HUGE!). Please, please at least try to start putting some no-contact time together again and find a way to make it stick.
Big hug to you and keep posting.