Well, peanut butter is so sweet and stuff, as opposed to an unrequited love, meaning a love where one person who loves someone is not loved in return. This is not sweet at all. It's very bitter and something no one wants as opposed to peanut butter, which has a sweet taste. So a bitter, unrequited love would take that sweet taste out of yummy peanut butter! =) I hope this helped. I love the quote*sam