As you mentioned, you may choose someone who does not choose you (unrequited love). This leads to a more genera question, or two.
What if everyone adopts the 37% rule; does that lead to everyone, or no-one, getting their choice, or does it make no difference?
More generally, there must be a stopping rule which maximises the total number of optimal choices across the entire population; surely, this would be the rule 'discovered' by natural selection?