God, the NTR in this game is so organic that I have no idea why people bitch so much about the content levels. Of course the NTR side is going to be higher. Your mom and your sis have never seen your beta male ass for anything more than nerdy loser son/brother. They aren't going to hop on your dick the moment you start to show a spine. It's a large leap from people who show no interest in you, to becoming more loving of you, to becoming infatuated with you and finally wanting to do anything sexual with you.
On the other side of things, your mother and your sister are going to more easily take to the idea of dating/sleeping with other people. The other girls in the game know Marcus/others better than they know you. You're a stranger. They aren't going to hop into bed with your as fast as they would him because they don't know what kind of person you are. The Alpha path is slower because you have to both defend against others while presenting yourself in a positive light.
All that being said, the Alpha path has had multiple points of sexual content with girls outside the mother and sister so I really don't get the bitching. Handjobs, blowjobs, pussy eating, sex, lots of nudity and yet that's apparently not enough for the Non-NTR side to stop bitching.
And the NTR side is just as bad, you guys get the good end of the stick in this game, stop bitching because the Non-NTR people get shit too. This was never a single path game. It was always 2 to 3 paths.
Just stop.