Honestly we can't make a decision regarding whether Mai is being an idiot over the Luna situation until we know why they broke up. It could be they decided they worked better as friends.
Given the framing I highly doubt that but I do empathise with her desire not to lose a friend.
I mean we do know why they broke up. Ex-gf said they would be better as friends and they even met up so she could help her shop for an outfit for a date with her new boyfriend. She just stopped meeting her because she has a new girlfriend now.
The ex is sounding a little self absorbed to me. Doesn't seem to notice how much the breakup hurt Mai, despite her boss saying how obvious that was. Also man, I know they were best friends, but having her pick out outfits for a new boyfriend? Damn.
God I just wanna eat parfaits and have sex with these two so much.
Thank you for the translation (that parfaits they were eating looked amazing. Truly a work of art. I'd love to go to one these night parfait shops one day