.just go with the flow..tell them you have a super nice and handsome guy and when they ask you who, tell them about ur favorite bias..

Tell them you want to focus on your studies or ____(something important for you) . and that you waiting to find someone honest and grateful. And especially hardworking. :) I got you.

ooooh I need help with that too lol! I even tell them if they aren't a kpop star they won't be my boyfriend!

Tell them you're in a committed relationship with your refrigerator. > _ <
If you're not interested in being in a relationship yet, just tell them that. Reassure them that you are as single as a pringle and that when you do get into a relationship, you'll let them know when the time comes. But it's really annoying you, then tell them it's simply none of their business. It all comes down to how you want to handle this.

I don't know, unnie because I go through the same thing. And I'm tired of shrugging, rolling my eyes and telling them, "I'll tell you when I already have one."

As for me , if they ask about this kind of things , i will tell them with honesty. Seriously."!
i Don't give a , if they dont want to believe it. Dont care . hahaha .

oh and happy belated birthday my dear! <3

I have the same issue too lol. Ever since my grades gone down, they kept asking me if I have a boyfriend because my grades went down. I kept telling them no. And they stopped.
In your situation, you should "fake" an outburst and yell "I don't have a boyfriend! (Or girlfriend if you're a guy) I've told you so many times before! Do you ever listen to me?!" and, my dear, I can guarantee you that they will almost never bring it up again.