"My perspective about kids has changed as I've gotten older. I never babysat or anything. As a teenager, I was like, 'I'm never getting married, I'm never having kids'," she told the magazine.
"And then I got older and I was like, I really want to get married, I really want to have kids."
Stone was spotted wearing what looked like an engagement ring in April, but this is the first the couple have confirmed they're set to tie the knot.
Posting to Instagram, McCary, 34, shared a photo of the two grinning, simply captioning the snap with love heart emojis.
McCary, 34, a writer and segment director on Saturday Night Live, met Stone, 31, over two years ago, when she hosted SNL.
Before McCary, the La La Land actress dated Andrew Garfield from 2011 β 2015, after meeting on the 2011 set of The Amazing Spider-Man, where they played onscreen couple Peter Parker and Gwen Stacy.
Prior to Garfield, the actress dated Kieran Culkin, the younger brother of Macaulay Culkin, and was previously linked to singer Teddy Geiger.