You need to revise you "sex between us" deal. She seems like a nymph and, believe it or not, more and more girls are becoming like that in our day and age. If you want to be the only person having sex with her, you need to change the deal to say you both will do your best to spice up your sex lives so as to satisfy both the intimate and the horny cravings.
It should do the trick. If by then she's still fooling around, she's a moron.







