The first time, both him and the girl were drugged so he couldn't do anything against it, so they had s*x. end.
The second time, he was supposed to marry a girl, but she didn't want to marry him, the MC would have agreed with her and wouldn't have married her if she didn't want too (since he didn't really wanted to marry her either)...
But that girl, instead of just talking with him, decided it was better to drug him and send her best friend to have s*x with him, to force him to marry her friend instead of her.
So he was drugged and needed to have s*x with a girl, but when he saw what was happening, he refused to have s*x with that girl friend and went after her instead. She totally deserve what happened to her.
She wanted her friend to rape him, well she got rapped instead, serve her well.