On again off again relationships

My boyfriend, let's call him Brad, and I go way back. We were best friends for years before we dated. At the beginning of our relationship things were so good, actually throughout the relationship things were good. Until him and one of my closest friends Maggie became really close. Although they never did anything physical, he lost interest in me due to the time he spent with her. We broke things off after 2 years of being together and we stayed separated for about 6 months. In that time him and Maggie started seeing eachother. I never thought I would be with him again. He was with Maggie now and I was beyond hurt. I met new people but nothing was the same. I didn't hold on to anger with those two but it always hurt because they went against my wishes and I felt betrayed by both of them.

One night, at a mutual friends get-together, Maggie wasn't there. Me and brad reconnected and ended up going home together that night. We continued this for a while but Maggie found out. I felt bad for hurting her, I didn't want to sabotage their relationship and I didn't do it out of spite. I did it because I still loved him and it felt right. 

Maggie ended up forgiving him and wanting to work it out but he was still asking me to hangout, so she left him for good.

Brad and I were enjoying new beginnings but now I'm not so sure. We have so much fun together but when were apart he acts unhappy. I've told him that he doesn't have to stay but he does anyway. He ended up getting drunk at a party and kissing another girl which hurt my feelings a lot. He tried really hard to keep me and I told him I would stay. He started to act interested again and said the idea of losing me after he kissed her scared him. But that lasted for about a week. He seems so uninterested and he says he feels chained to me. I know that this is unhealthy but when we're together in person he seems so happy. He told

Me he's lucky to have someone love him the way I do. I really love him unconditionally. He's also told me he's glad to have someone like me in his life. Things feel right when I'm with him.

I'm unsure what to do this is a text that he sent me recently

"I'm gonna start by saying that I love you and a part of me will always love but I don't know if it is always gonna be the type of love that you want. I don't want to hurt you for not loving each other the same way. I think that we do both love eachother we are just doing it in different ways. But then it becomes a want for different things, I don't know this for sure but it feels like you want things back to what you saw/see as the normal us. But I don't know if I am ready to just get right back into it as if nothing happened. I don't know if we are going to be able to work out the differences in our needs from this and how we think we should love eachother"

I'm unsure of what to do. I know that the easiest answer is to leave him and move on but I can't just give up. I really love him and we've been through so much together.  Any advice, has anyone been through this before? Please help!