feeling raw after an open relationship convo

i just had a really tough talk with my partner tonight. we've been in this open thing for over a year now and tonight he mentioned he's thinking of exploring some kinks i'm not into. like, it's cool if he does but... hearing about what he wants to do makes me feel kinda icky inside. we agreed on a no pressure situation but i'm struggling with all the feels. don't know how to handle this space between us where boundaries are getting blurry and emotional walls are up.