Boss not wearing a mask

I’ve been working at this company for more than a month now. And he never wore a mask, which was fine by me, cause I always wear mine.

Not so long ago I found out I was pregnant, so my circumstances have changed and while I keep wearing my mask and doing my best at keeping my distance, sometimes he sits too close to me (when we’re reviewing designs on my computer, etc.). I don’t really wanna tell him I’m pregnant yet, before a) it’s too early into the pregnancy and b) I’m worried it may affect my job as I just recently got hired.

Any ideas on what I can do or how to talk to him about this?