so... her ex is her mom?

Considering her mom isnt around the house and homika's trauma she's probably either left or dead. Mei's caring feelings are probably reminding her of what she's lost. As for why she's disgusted by it, i dunno maybe she doesnt want to equate her lover with her mother or something like that? She feels responsible for her mother's disappearance and has lasting trust issues? the depth inferred in this manga is interesting

It's not every day I see mommy issues inserted into a character without any such thing in the canon, especially a Pokegirl as simple as Homika.

I thought her mother was dead too, and then this woman shows up on page 31 that totally talks as if she's her mom. What the hell.

Homika with her hair down is cute, reminds me of Sayaka because seiyuu connection

Not what I expected. And yet, I really liked it.
This world needs more PokeYuri.

What exactly is the backstory to this? lol

Well... was OK, I guess..
Kinda cool to see that the people around them (even the parents) are supportive.

Homika (aka Roxie in English) is a gym leader in Black and White 2. She has a dad but not a mom. So the mangaka seems to have made up a story about her missing mom lol. The real Roxie in the game is not angsty at all and gets along with her dad.