This mistress needed to dominate this guy with her chastity device and she did it without caring about how he felt. The mistress was interested in making sure that he was in pain and that he learned not to mess with her. He tried to beg her to stop but she did not. She ignored him and she went ahead to do whatever she wanted to do to the guy.
This mistress did not feel like her husband was going to be faithful to her. She did not trust him but she did not want to leave him. So she chose to use her chastity femdom to dominate as well as humiliate him. That is why she went out of her way to force him to wear a chastity device and she locked it and hide the key to control his use of his dick.