Is this a game where you have to be a jerk with every girl to get the sex scene ?

No judging if this is what you like, I just wanna know if I should play it or not. Because it looks great, but the comments makes me doubt.

Not really. For the most part the story is linear and you unlock all the sex scenes no matter what. The protagonist honestly isn't even really a bad guy, but a combination of circumstances and ignorance force him and the girls into bad spots, and the story can get dark at times.