"Am I really about to do this all over again?" should be the freakin' title of the manga.
Kaede was extremely unlikeable in this chapter, but it was in a way that feels true to her character. She's a shlub who keeps being given opportunities to grow up and keeps rejecting them, so sure, she'd somehow be dumb enough to miss how gay Nanami is, and then somehow be thoughtless enough to choose Koyuki of all people to whine about it to. If getting called out about it by a freakin' teenager doesn't wise her up, what's it even going to take?
It's always weird to me in manga like this that someone like Kaede never seems to find it particularly weird that women keep confessing their love to her. Earlier, Nanami's character arc actually dealt with the gay thing, so it's especially weird here. You'd think she would spend at least a little bit of time wondering why she's found herself gravitate to lesbians and bi women throughout so much of her life, something.