I managed to get the "love you" scene while playing blind. Seemed pretty obvious which choices would probably negatively impact your relationship with the girl who has obvious fears of being cheated on.Sage path - not only all the other girls are unavailable to you, but even scenes with Sage become unavailable due to cheating points. Okay, if you're groping girls, then yes, but points for cheating for flirting, joking, or even talking to other girls. This is insanity, it is not surprising that many are unhappy. I guess the branches for Jill, Bella, Josy/Maya aren't any better.
Frankly Sage being that paranoid weeks after finding out her previous boyfriend was cheating on her is one of the more believable plot elements.