Am I wrong for being upset?

I’ve been with my boyfriend for over three years. We talk about kids, marriage, our future. I thought we told each other everything. Then today he tells me he saw something on fb that describes him.....it was about men not saying how they feel and keeping everything bottled up inside. I told him I thought he tells me everything and he said no. I’m kind of hurt. I asked what he hasn’t told me. I asked if we could talk about the things he’s holding inside and he replied “mows not the time”. He says I’m over reacting, am I wrong for feeling sad? I tell him everything and thought he did the same. Why marry someone you can’t talk to?