The cuck cumming 4-5 times a week is way too much. His willingness to serve and obey diminishes when he orgasms. Depending on his age, it can take 1-2 days before he is back the way you want him. I recommend starting with 1 week and see how it goes. Then progress to 2 weeks. If he's watching you get fucked that often, he will be in a constant state of arousal, and therefore, very obedient and eager to please you.
Also, when you do allow him to cum, his orgasm should always be associated with your pleasure. Have him lick you to orgasm while he jerks off. Only allow him to cum after you do.
Also, when you do allow him to cum, his orgasm should always be associated with your pleasure. Have him lick you to orgasm while he jerks off. Only allow him to cum after you do.