I think that a similar thing happened to me.
I was with someone but I wasn’t happy because I really didn’t love him. I was forcing myself to settle just because I was so eager to be with someone and because he was totally different from the other men I’ve liked and had made me suffer. He was kind, gentle, etc., but I suspect he was in the same situation as me, that he didn’t really love me too, but was feeling lonely, as he soon started to pressure me into spending more time together and making plans about moving in together when we hadn’t even been dating for 3 months. I soon fell into a depression and deep down I knew I had to end it to heal myself and move on, but I was too scared of loneliness as well. Fortunately he sat me down to talk one day and that was it, we split up. I cried a lot, I felt really really sad for days after that but I knew it was the right thing to do. Then I started seeing a therapist to work through my self esteem issues and I eventually felt better. I actually regret I hadn’t gathered the courage myself to finish the relationship sooner.

What I want to say, your BF might be in the same situation as I or my ex was.
It’s going to be painful, I know, but if you love him, set him free, it’s obvious that he’s suffering. You are suffering too, and you don’t deserve that -on one does, actually. If he’s the one for you, you’ll eventually end up together, but if he’s not you’ll move on and grow as a person.
Have you tried going to therapy? Sometimes our demons are in our own heads without us realising. I really hope your problems dissapear soon and you are happy again. BTW, sorry for my English, it’s not my mother tongue, but I hope I’ve explained myself well. Big hug.