My grandma called her boyfriend "partner" that she had while I was growing up (they dated for almost 20 years, but never married because she would have lost one of the pensions she was receiving as a widow).<quoted text>Hah! I was thinking the same thing afte I wrote my response. I don't know any hetero's who use the word partner. No matter the age, its bf or gf.
It was always, "this is my partner Al" not "this is my boyfriend Al". Al died over a decade ago, so she was using this terminology 20-30 years ago.