I can't believe best girl got rejected right on the last page!

Oh no! Rio got the friendzoned?!?

Time to use the "If we're both still single in five years, then we'll get married." card, just like your mother used to.

Yeah i dont get why blondies Devotion is being questioned, she hasnt been acting out of line nor has she been particular negligent

Let me remind you that they married as friends, Kurumi (the "blonde" one) up until now has never thought of Ruriko as anything more than friends. Also Kurumi was the person who made up the 5th rule (if one of them fall in love with sb else they will go back to being friends).

It isn't that she hasn't done anything to be questioned, but that Kurumi hasn't done anything to prove that she wants to stay in this marriage. Sure, we as the readers know her thoughts and know what she wants, but Ruriko doesn't. From Ruriko's point of view, they're staying in a marriage of convenient without love and Kurumi is always just one step away from walking away from it, it's right for her to be scared.

Isn't it the same for Kurumi? She doesn't know why Ruriko married her, so Kurumi has the same POV as her.

This series was okay, but I liked the author's previous manga "Crescent Moon and Doughnuts" a lot more. A big part of that was that Crescent Moon and Doughnuts treats asexuality as something that should be discussed and navigated, whereas here it's what our two "friend" protagonists silently default to, and that's a very common and very annoying pattern. It's not just old yuri manga: to this day it's still really common in depictions of lesbians, and there's still a cohort of really annoying people online who will accuse any media with lesbians expressing physical desire or having sexual feelings as "pandering to men" or even straight up being "media for men".
This manga fits into what that group would want and does it silently, whereas Crescent Moon specifically treats that as not a norm but rather something to be navigated. Personally I don't like it when any romance that treats any part of a relationship as something with a default you can just have without addressing it first, and that goes double for queer media. I hate all those unigender settings in GL and BL where nobody even needs to consider if the person they like is gay or not. Burn down every private all girls school in manga imo.

Now that I think of it, I can't think of another series that has that family dynamic (besides maybe I'm in Love with the Villainess)? Unless someone has recommendations?

She Loves to Cook, and She Loves to Eat has some pretty strong found family themes, especially in the latest English volume.

I haven't read that one yet. I'll look into it. It seems hard to find those especially involving a family with children. The only one that I know of that has this and actually spends time with this dynamic is the one I mentioned in the spoiler.

Two best yuri manga for families with two moms and children imo: Days of Love at Seagull Villa, and Ohana Holoholo. Both have the kids involved right out the gate as something one of the main characters is bringing with her into the relationship. Days of Love is very fluffy and cozy, Ohana Holoholo will make you earn the fluff by suffering with the characters through their trials and tribulations. It's worth it though, very worth it. :)