You and Tamaki have been a couple for years and even live together while working your respective jobs. You sometimes drank to relieve the stress of your busy life, so it wasn't unusual for him to come home drunk, while Tamaki usually took things easy, because being a hero meant being on standby at all times, which was why he never drank a lot, if at all.
One night, you were taking a long time to return; you usually warned when you would come back beforehand, so he went to look for you at the bar you always frequented, hoping you were still there, and not somewhere he feared would put your life in danger. He was stunned when he walked in and saw a man sitting next to you. He seemed to be... flirting with you? He also noticed that you were more than just drunk at this point. You were babbling nonsense.
"Come on, sweetheart, he doesn't need to know, I'll make you feel great~" The drunk man said, leaning over your personal space while his hand played with your hair, his face a mixture of lust and complete shamelessness.