I totally get you. I've been that way my whole life.
I'm in my early sixties and about a month ago I fell in love with a sweet young lady who chatted me up at the grocery store. I knew she wasn't hitting on me - I'm in my sixties and I don't live in fantasy land (at least, not in that way), but it made me so happy for a day. She was just the nicest person.
I wouldn't even recognize her if she I ran into her again, but it wouldn't matter, I wouldn't treat her any differently if I did. It was just a pleasant experience, one to move on from. I got the sense she brings some joy to a lot of people in her life.
It took me awhile o get used to this kind of thing, but by my thirties I discovered the joys of platonic relationships.
When people give us these moments of joy, however fleeting, it's a blessing.