The size

So my bf and I have been dating for almost a year and we have had sex and all that fun stuff but when I ask how big he is down there he won’t tell me. I get worried that he feels like I’m gonna leave or something. I get the pleasure I need and I love him but I want him to feel comfortable telling me stuff. How do I get him to feel comfortable telling me this stuff? I’m 21 and know size DOES NOT MATTER. But I want him to feel comfortable telling me personal things cuz he always makes me feel comfortable telling him personal stuff.

Don’t judge me for asking this but after all of my girlfriends knew there mans, it occurred that maybe mine isn’t that comfortable with me yet. 😔😔😔