I think Kina was frustrated with Megu because Megu never told him his feelings, and I suppose he thought it would be a little lame to ask him: do you love me? Anyway when Megu got jealous he finally realized that Megu loved him. (▰˘◡˘▰) kind of simplistic but cute, at least there was no rape!
I don't get why Kina became cold kskskds I seriously despise plots that involces miscommunication/a problem that's solved by talking
(╯°Д °)╯╧╧
On the other hand, the second couple!! ლ(´ڡ`ლ)