He picks it up, and suddenly he’s all “Hey, how you doin?”
a full octave lower.
You just know the caller is a) female and b) pretty.

Wow, thank you, science.
What’s next, you’ll prove that night is darker than day and donuts taste better than broccoli?
Still good news, if not quite as flattering.

TheJournal of Phonetics(viaScience Direct) also brings up yet another reason behind vocal changes.
So again, not necessarily a romantic thing, unless you’re starring in aromcom, of course.
In that case, happily ever after is but a montage away.