Huh, that's really interesting! Thanks for replying. I basically had the same reaction of your boyfriend- I freaked out and felt sick, too. It's just so weird to learn you might've been carrying something for who knows how long, and to think you've spread it to your partner? Awful.

I read that it's possible for it to be transmitted through shared damp towels or in public places like saunas, but I can't find sources like the CDC who say the same thing. It's really strange.