@Kamui she could be bi, but most likely she just went along with the flow and didn't want to hurt him
not that everything needs a label, still, what she did was perfectly understandable
now the main couple, however...
in chapter 3, Maki casually confessed that she still liked Midori, thinking the other was fast asleep but Midori replied, half-jokingly "i might be falling for you too"
now i just need Midori to make up her mind about what she wants and then gives things a proper end to it, before she comes to Maki
i mean, them raising another guy's kid together isn't the worst case, after all, the kid is still half Midori
just. dump. the. guy. this hurts