Confession: I love Bad Dad movies. I eat them like candy. Bad Dad, Bad Husband, Bad Stepdad, all of 'em!
And lately my recs have been full of these so I'm kinda living for the melodrama. Anyway, to the point, there's a trend over the past handful of years or so:

The straight wife/mom character has an Incidentally Lesbian Sister. It isn't something that's talked about a lot but we see her partner, or she mentions she'd like to have one, along those lines. She just happens to be gay, nbd.

As representation it's kinda bullshit but it beats none, so An Effort Was Made-level points, but here's my favorite thing:
She's usually the adult who knows what's really going on! There may be a child or two who also does, but Incidentally Lesbian Sister, you can COUNT on.

Most recently spotted in Dylan Walsh vehicle (yes that's a real thing that I really said) THE STEPFATHER (2009). Not all that recent, but an awesome example. I ate this well-cast trash with a SPOON.
Paige Turco, as Incidentally Lesbian Sister, Jackie, predictably is wonderful...

While Sherry Stringfield is Jackie's partner, Leah, and though barely shown, also wonderful, naturally. Minor spoiler, Leah does not put it together like Jackie, but her character is joyful and sweet, a nice note here.
I'll be on the lookout for more Incidentally Lesbian Sisters!