chapter 15 they start cohabitation, Hijiri is jealous of a guy who works with Koyori - they meet when Koyori was shopping with that guy - it becomes awkward and that other guy leaves - ML leaves Koyori with some cold comment, Koyori is crying. Chapter 20 they reunite and Hijiri has aggressive sex with her (? - prob cuz he is jealous) and they continue on it to the next chap (21)