21 year old can’t have sleepover

This may sound really stupid. I am 21 years old, graduated college, and have a full time, salary job (I am a teacher). I live at home, because well, it’s easier in this economy.

My boyfriend and I have been dating for almost 7 years. My parents aren’t his biggest fans :/ However, I’m not allowed to have him sleepover or sleepover at his house. I feel like this is a little silly, considering we are both grown(ish LOL) adults now. How can I convince my parents otherwise?