Most Helpful Guy
First of all you need to end things asap. Make it clear to him why he´s toxic to you so you get some closure. After getting rid of a bad relationship, take some time to think about what you actually want and why you want it. When your end goals are clear, it´s easier to start looking for a partner who shares your values and life goals.
It all starts with you deciding that you´ve had enough! If there´s some underlying trauma or tragic past that makes you question yourself, please seek help. I´ve had a troublesome childhood and until I took care of past traumas, it was hard to relax in a relationship and really enjoy life.