i disappointed Mistress last night :(

During the training session Mistress ordered me to remain kneeling in bondage while She went to get something to eat, but i moved to go put on the heating. Mistress was very displeased with me and i was dismissed for the night. Mistress also called a lover over and had sex with him, i wasn't allowed to go to bed until She was finished with him and had to wait until 2am before going to bed. The thought of Mistress with another man is really upsetting, it is the worst feeling i have had since Mistress collared me.