This was interesting. I wasn't expecting the continuation to go this way, but it makes sense given Midori's characterization. She knew Baba was cheating on her for a long time, that was never news to her. And it's also true that her face seems permanently locked into that sort of pleasant smile, so if Baba is one of the few people who doesn't mind that it makes sense she finds it relaxing to be around him despite his...*many* flaws.
Still, this is definitely a unique direction for a romance manga to go. As cute as Kyouko is, Midori is fast becoming my favorite character; I don't think I've ever seen someone quite like her.