Suggestion from Q42 Community:
Yep that’s pretty annoying! Some people are just convinced everyone must find them irresistible…
How many times have you had to tell them? Sounds like a few!
Sometimes you can take the wind out of their sails by make light of it first with a joke, before they have a chance to comment. If you’re making fun of how daft the idea is before they can say anything it can quickly take the fun out of for them too. Or flip the situation and make similar comments about them that assume they fancy everyone of the opposite gender that they see (although sometimes that can backfire!)
It can be a pain but this sort of thing does pass eventually, like anything the novelty will eventually wear thin.