You say here yourself that his beliefs are not compatible with you as a person. And yet you're still trying to make it work?

He isn't going to understand that his statement is fucked up because he doesn't want to understand. "Boys will be boys" is such a harmful dismissal of the actual issue. There isn't really a "biological inclination" to want to rape someone. You've already tried to explain that to him and he just wants to "agree to disagree" and sweep it under the rug.

You can either let him do that and be okay with it, or you can stick up for yourself and refuse to carry on in a relationship with a guy who thinks that he's just biologically wired to want to rape you but his "emotions" keep him from doing it.