He can’t control his thoughts ??

My bf says he can’t control his sexual 5 second thoughts about other women/his female friends He told me that he has thought/thinks about cheating on me before because a voices in his head but he “claims” he will never act on it. I told him “it hurts because I never once thought about having sexual stuff with other men” then he said women and men are wired differently & I’m overreacting. Basically undermining my feelings. I’m really hurt right now honestly. I never knew that he thought things like that. I thought I was the only women on his mind he thought about doing things to. Opinions ?