Evita, I finally found out: they didnt have sex.
In the episode when the daughter finds out of the relationship between Maru and the mother she asks him why he didnt try to sleep with her. And he answers that he only wants to do it with the mother. Ouch
Yeah, he was so intent on hurting her
Did you know that the full title of the drama is "There's no such thing as nice guys"? Pretty appropriate