I'll never let this go.

The worst feeling is when you realise the person you love has changed.
I'm going through that right now, and I hate it.
Me and him were the closest people you could ever meet.
We still are, I guess. It's just different.
Because he's changed, a lot. Not necessarily in a bad way. Yet I still don't know if I like it.
He's so sweet to me. He treats me amazing, makes me feel so amazing.
But he's different. I'm not sure what it is, to be honest, but there's something strange.
I'm not going to let go and give up on him. But it's not right.
I want the old him back, I honestly do. Which I suppose isn't fair of me.
I don't want to lose him, but he's not the person I loved. So what do I do?