How to break free of a no-good leach and live my own life?
The questioner's philosophy
Maurice's reply: This is an unhealthy relationship to say the least. This man is an emotional and economic vampire. He will suck you dry in every way imaginable. He is a user.
You found a place at college where you feel really good about yourself. Why don't you expand on that. For people in your age group there are usually Senior Students Associations or Mature Students Associations, a way of expanding your friend base and broadening your horizons.
See the Student Counselor at your college to get the advice and guidance you need, to sort your finances out and to free yourself of this ball and chain... so you can devote your life to your studies, your college environment and new friends, and to make progress toward your goal in life, to become a math teacher.
For home base, get a cat or dog, someone who actually appreciates you and throw the bum out. He's a leach, pure and simple.