he wants to wear womens lingerie

So my boyfriend has informed me the other day that he like to wear womens lingerie and he likes butt play and wants me to dominate him w a strap on. Now i’ve gone out of my comfort zone in the past when it comes to sexual experiences w him but this isn’t something i can get on board w. and I feel shitty but i don’t even want to be w him anymore bc of this. i don’t want him to think i’m judging him, but this isn’t something i’m into and i don’t want to be w him anymore if it’s truly what he wants. i’m trying so hard not to sound like a bitch but it’s just my preference and i’m not into it. I’ve tried to explain to him how i felt and now he’s trying to say it was just a joke to see how i would react but he’s shown me amazon purchases where he’s bought these items so i’m not sure how it’s a joke? and i also don’t want to stay w him if he’s going to have to hide who he really is or the things he’s likes. i just don’t know what to say to him, i don’t want to hurt him but i feel like i’ll hurt him no matter what i do.