RAPE KINK

My SO has a rape kink, and it terrifies me, as I previously have been sexually assaulted. He's never even told until now while we were sexting he asked if we could do a "play rape" fantasy. I first started suspecting when I was riding him and it hurt and he didn't wanna stop. After I told him it actually really really hurt he held me and felt like shit because he didn't wanna stop. He knows I've been sexually assaulted btw.