bro, why don't you try another bro's method? no offense.. just a suggestion.. try to use alittle more force to force yourself on her once..
there can only be two possibilities:
1) probably she haven't found the pleasure of having sex yet so if you force yourself on her, she may end up liking to be fucked by you cos you showed her you're her man and you're in control. happy ending.
2) if she forcefully retaliate and ends up slapping you or crying out loud saying "no! sob sob sob".. you know that this is not a marriage you want..
what do other bros think?