Eye contact ugh

So my boyfriend and I have been dating for almost 2 years but we have a problem. I don’t make eye contact as much as he wants me too. Like we will be talking serious and my eyes will stray or when I’m trying to be serious I can’t look him I the eye. No matter what I can’t look him in the eye. But when we do it’s so intimate and it’s so sweet but we’ll be talking and he’ll say something like. You can’t even look me in the eye and I feel Terrible. And no I’m not hiding anything from him. And it something I do without thinking.