Similar to "better half", used to refer to a significant other who's also significantly gayer.
eg. Bisexual partners of straight folks, gayer partners of gay folks, women partners of men.
Straight Stan: I can't come to the moshpit, Straight Stacy wants me to come home and cuddle
Patriarchic Pat: you faggot we know you want to go home and cuddle, don't blame it on your gayer half
Straight Stan: yeah well that's female privilege ain't it? They don't get called out. They get away with gay. What am I supposed to do?