Sex between a man and a woman is a naturally dominant male act. A submissive man will never be good at penetrative sex. Oral sex is the domain of the submissive man and he does well there. Many submissive men wear a chastity belt and have a certain denial period that is good for their behavior. During that period, the penis is unavailable to the dominant wife. When the denial period expires, the submissive man ejaculates quickly and just as quickly crawls into the cage.
The real man and his skills in penetrative sex are essential for a dominant woman. Most submissive men know this and support it.
Cuckolding can take many forms that are not humiliating to a submissive male.