The Bachelor 's Joey Grazadei and his fiancée Kelsey Anderson are perfectly compatible - and it's all because of one popular relationship theory; the olive theory. The tennis pro recently posted a picture on his Instagram Story of his winner and future wife while the pair were out for a meal. Kelsey - who wore a gorgeous yellow dress - was seen making a disgusted face as she sat across from Joey at their outdoor table.

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According to USA Today , the "olive theory" comes from the sitcom How I Met Your Mother and is first mentioned in its pilot. Main character Ted recounts his and Robin's first date to Lily and Marshall, calling Robin "the future Mrs. Ted Mosby.

" Robin checks off all of Ted's boxes for the ideal woman, and saves her best attribute "for last." She hates olives while Ted loves them, and the "olive theory" is based on Marshall and Lily. Marshall hates olives, while Lily loves them, and "in a weird way, that's what makes them such a great couple – the perfect balance," says Ted.

It might seem like the theory is similar to the idea that opposites attr.