Very confused

About 2 and a half years ago I started going out with this boy. We dated for about 3 weeks before his father decided he hated me (because I had a short history of self-harm and my religion is a pagan religion) and we then weren't allowed to date. The boy found a way to talk to me online secretly and has been hiding me from his father for more than 2 years. We go to the same school and we even have classes together but as far as everyone knows, we are strangers. Our only form of interaction is over text and Kik messaging. Sometimes we sneak out into the woods after school to be with eachother for a short time where no one can see but this only happens maybe once a month and it's the only way we can see eachother since neither of us can develop yet (although I have my permit and can get my lisence in a year). Last school year (my freshman year of high school) my boy decided that he liked another girl a little and she liked him back. This girl bullied me and made all my friends hate me and I hated her with a passion but I couldn't tell him. He said that maybe if he dated her for a while he could tell his dad that he tried to date other people and it didn't work out and that he still liked me. He said it might convince his dad to allow us to be together. For about 2 months I was forced to watch him, who I loved with all my heart, hug and kiss another girl, and he still texted me every night saying he loved me only. I resented him for it. I was suicidal and I told him that and he didn't do anything. One day I finally told him it was between me or her and he broke up with her. But it never stopped hurting that he did that to me and that he was the reason I wanted to die and he didn't care. After that our relationship fell apart and we would always fight and he became very disrespectful and mean and all he ever wanted from me were nudes. I thought maybe he resented me for making him break up with that girl because he still liked her, even though he promised me he didn't.
Finally resent it everything fell apart. We had a huge fight and I ended it. But he begged me to take him back for a week and for the first time in a year he seemed sincere. So I gave him one more chance. Now we are talking again and he's doing so good. We haven't fought and he's being so sweet.
A year and a half ago he said things like "I love you more than life itself" and "You mean the world to me" and "I'm gonna marry you, one day" and my heart would skip a beat when he did. Now he says things even sweeter than that and I feel nothing.
I want to love him so bad but I just can't make myself anymore. He's trying so hard and it's gonna hurt so bad if I break up with him but this isn't working. 
I'm so stressed and confused.