Diabolik Lovers Is Just a Few Bites, Right?

Who do the male protagonists like? Has the female protagonist been abused all the time? The only one who will do that to the female protagonist after a while sucks. I feel that the male protagonists are so dirty. I hope that the female protagonist will not be with anyone.

There is no male protagonist in the book, so why does he interact with Si Lian the most?