hey girlie, he rejected him romantically, but wants to remain in the dom/sub relationship and continue camming with him (which was what they agreed to since the beginning...). it's hard to find a compatible partner in the bdsm community that you can trust with more complicated plays so I get why he really wants to keep MD as his dom. but after this chapter, yikes. I agree with you - he NEEDS to leave.
Chanwoo was LITERALLY hurt because his 3rd person (who he brought and allowed himself be manipulated). So, after learning his true intentions he felt upset with himself.(he said it. Read the "mate" part again.) After reading it, let's see if that facial expression doesn't scream,"MY PRIDE WAS HURT!!"

cant really judge the slap since i dont know if that's okay with them in their scenes, but WHEW........
one part of me thinks this is too far, but the other is wondering why chanwoo doesn't just go? he rejected MD already, why go through this o_o