The Good NTR route is fantastic! It's the closest thing to a Stag & Vixen relationship with your girlfriend where you mutually 'cheat' on another is right up my alley. I love it when MC is dominant and in control of it all towards the girls and the girls are complete sluts, sleeping around while loving the MC in their hearts.
I personally don't like virgins, I like experienced girls because they know just what they want in bed so hopefully she can lose her virginity to some other boytoy like David so we don't have to teach her the ropes.
Perhaps she could do it behind the MC's back in the Bad NTR route, and a choice for the MC to consent doing this with David or do it himself for the Good NTR route.
EDIT: I don't know if dev reads this, but I wish there was an option where we can keep Kelly's bad-girl model.