Weird man came to my apartment. Should I be worried?

I (23F) live alone in an apartment complex and something weird just happened… (also I’m typing this on my phone so sorry if the formating is weird)

To give some context, I recently started dating my friend, and he’s come over to my apartment 2-3 times already. I don’t live in a big city, kind of countryside so people are kind of relaxed around here. Anyways,
Right now, some random man, maybe in his mid 40s? rang my doorbell. I ignored the first time, thinking it was a solicitor or something. Then, an hour later he came back again. I remembered that someone had recently moved in to the apartment complex and I opened the door thinking it was just someone introducing themself.

Well instead, this guy proceeds to tell me that he’s seen me with my boyfriend and told me to be careful. He said he had a friend that was in a relationship with a guy and the guy recorded her doing “youknowhat” and that I should make sure that doesn’t happen to me….?
I’m a bit spooked because I’ve literally never seen this guy in my entire life and he doesn’t know me or my boyfriend at all… Not really sure what I should do, but I’m very creeped out. Any advice? Has anyone had this happen to them??

tl,dr creepy man came to my front door and warned me about dating my “Japanese boyfriend”