If Chanwoo has feelings for MD and realize them maybe MD will accept him and have him. If not, why did MD have to accept him while he has feelings for him that are rejected? As I said in another comment if your best friend confess and is rejected by you (it is your right and choise) it is also his right to stop be your friend because he can't simply handle it. Seeing you with someone else and not having you could be too much for him. Same for MD. If Chanwoo has no romantic feelings for him why not change Sub? Have you think what it is for him to have sexual acts with someone who does not want him while he does? So who said that he is playing a game? Indeed he may think that he either can continue with Chanwoo if their relationship advances (because maybe Chanwoo suppresses his feelings because he is always getting dumbed and afraid to lose MD if their relationship changes). Or if Chanwoo does not really want him as a lover is it logical that now that MD confessed he can no longer have Chanwoo as a sex friend, so the logical course is to take the new and willing guy?
If Chanwoo has feelings for MD and realize them maybe MD will accept him and have him. If not, why did MD have to accept him while he has feelings for him that are rejected? As I said in another comment if your best friend confess and is rejected by you (it is your right and choise) it is also his right to stop be your friend because he can't simply handle it. Seeing you with someone else and not having you could be too much for him. Same for MD. If Chanwoo has no romantic feelings for him why not change Sub? Have you think what it is for him to have sexual acts with someone who does not want him while he does? So who said that he is playing a game? Indeed he may think that he either can continue with Chanwoo if their relationship advances (because maybe Chanwoo suppresses his feelings because he is always getting dumbed and afraid to lose MD if their relationship changes). Or if Chanwoo does not really want him as a lover is it logical that now that MD confessed he can no longer have Chanwoo as a sex friend, so the logical course is to take the new and willing guy?