Personally, I think it goes like this: when Yashiro says "Don't break me" he is talking about the wall he has had to build between his heart and other people's. He is afraid of allowing himself to love and be loved because he does not want to be abandoned after that and therefore be lost and all alone again. Not loving is not losing. He does enjoy sex without pain, but sex without pain is not "sex" anymore but "making love". That is why all that sex with other men during his life was just something carnal. His body grew "accustomed" to be mistreated while sex intercourse and he associated that as something normal. That is why he says he feels like "puking" because of the way Doumeki touches him: it does not hurt, but psychologically it is hard for him to deal with it because he is being treated with care and love.
Personally, I think it goes like this: when Yashiro says "Don't break me" he is talking about the wall he has had to build between his heart and other people's. He is afraid of allowing himself to love and be loved because he does not want to be abandoned after that and therefore be lost and all alone again. Not loving is not losing. He does enjoy sex without pain, but sex without pain is not "sex" anymore but "making love". That is why all that sex with other men during his life was just something carnal. His body grew "accustomed" to be mistreated while sex intercourse and he associated that as something normal. That is why he says he feels like "puking" because of the way Doumeki touches him: it does not hurt, but psychologically it is hard for him to deal with it because he is being treated with care and love.