My boyfriend is my partner, but not my husband, though we've been around for longer than many marriages. For some reason, I don't think Chris would have had a problem saying wife were it so.
I respect the fight, but we don't all fit into the marriage binary either.
(And hey, maybe someday the two of us will be married too, heh.)
So I guess you could say he's your boyfriend. In the case of the original story you could say girlfriend or lesbian lover. Both terms are much better than partner.
"Partner" is seriously problematic because it really does deliberately evoke two profit seeking individuals in a venture, and that is not at all the basis of a marriage.
I respect the fight, but we don't all fit into the marriage binary either.
(And hey, maybe someday the two of us will be married too, heh.)