The evidence we have points to the opposite conclusion.

After all, in the last 30 years, we've had an absolute explosion in the availability of freely available adult pornography. If more porn access meant more rape and sexual assault, the rates of these should have skyrocketed over the last 30 years. Instead they've gone down. I wouldn't automatically conclude a causal relationship there. But if availability of porn causes rapes and assaults, then we would know that by now.