It seems to be, at least partially, a generational thing.

I grew up in rural, conservative-town USA and am old enough to remember when “partner” was code for same-sex spouse that I’m not legally allowed to marry.

Whereas if you were in a state where you were allowed to marry your same-sex spouse, then they’d be your husband/wife.

Hearing it now, regardless of orientation, just sounds deliberately vague to some of us oldheads.