stuck in a toxic relationship

i’m stuck and i have no way out of this relationship. i love my boyfriend but i have slowly began to loose feelings for an unknown reason, it might be that we have been arguing for almost everyday for a year and he’s very manipulative and controlling. i’ve brought up breaking up many times showing that i want to really badly in a lowkey way and he straight up just says “we’re not breaking up”, “i won’t let you”, “we’re still dating stop”. and i’ve just been so unhappy recently and i have no way out of this it’s a continuous loop. all of my friends say they support me and will help me with whatever my decision is and it’s really helpful but i just don’t know what to do. he says he’s going to change his ways but then a week goes by and he returns to his ways. i have been with him for 3 years and i feel like if i leave i won’t be able to adapt to another person because we are so close and he’s mentally abused/changed me so much over these years. he can tell that i have lost feelings and i don’t know what to do to get out of this and make him understand that we’re not going to get married and we need to experiment with other people. i am open to trying again in the future when we mature more to be together, but he won’t let me and ignores what i say about my feelings about how we don’t make each other happy and won’t let me out of this. please help and give me advice to be strong and find a way out of this.