I don't think there is anything to point up him being jilted over his love being unrequited. You take your pick, either fits.

My point about the impossibilities is that it is not two impossibilities, but everyone else saying "what do you expect, one of them could never go for one of us", while he is saying "why not. One of us went for one of them"

That's how I always understood it from hearing the Corries in the sixties. Whether or not there was anything in their introduction to lead me to that I can't remember.