Sometimes it's those dark parts of the world that seem interesting to explore.
Though he likes manipulating stuff and easily predicts how things would go, he still likes unpredictability.
Not to destroy anything, but if he was in the real world, one can say that if he got tired of Mayura, he can just as easily disregard her, like not being fun, being predictable, and the like. I kinda get why Mayura likes him, but I don't feel much of love from him - like 40% love, 60% amusement... or maybe 30% love? "Does he really like Mayura in the first place?" is what comes to my mind; but considering how the story goes... disregarding this and that...I think he still does love her.
Based on the genre I know he loves her. But I was about shook & taken aback by what he said. If it this was realistic all the things you said would happen most likely but this luckily isnt a twisted story so I know it wasn't the intent.
I feel of this manga wanted to it could easily go from 0 to 60 in the twisted department. Especially this look and scene Idk... It gave me those feels. I really liked it though.
http://www.mangago.me/read-manga/kanchigai_hime_to_usotsuki_shimobe/mr/c004/pg-45/