Don't scare me now
poor man's solution... set up an audio recorder ap on your iphone or droid.
hit the button while you're having sex, recording her screaming "yes" about 87 times. Then tell her to use your name, so there will be "oh yes BigGunzzz777, hit it daddy..."
Then, you can whip out your phone in the police interview room and ask Detective Flatfoot if that sounds like rape.