have a good relationship

I have a beautiful man for a boyfriend. We plan on getting married too. I’m really happy with him but I don’t think he is happy with me. He seems to be so down, he tells me he loves me but then calls me self involved. I thought I was giving him all the time in the world. I sit with him everyday in our bedroom. I just don’t know what it is I’m doing wrong. Why am I so shit at being in a relationship? We’ve been together for almost 2 and a half years, and lived together for 2 of those years and I thought we were doing really well. Aparently I’m really good at knowing things are there but deliberately leave them behind. I can’t get any more clarity on the type of things I leave behind, my boyfriend can’t tell me. I’m so confused!