This generation is radically rethinking straight sex and marriage, but at what cost?

In Part One of a two-part series, Rolling Stone goes under the covers in search of new approaches to intimacy, commitment and hooking up.

The honeymoon phase is the first few months of a relationship, when everything is new, feelings of attraction are intense, and it seems like the person you're with is perfect.

"But the other side of me was concerned about what this means in terms of intimacy and how the dynamics would work." When Leah and Ryan met at a wedding four years ago, they didn’t expect to develop this type of arrangement.

Neither of them had had an open relationship before, though it was something that Leah had contemplated.

In his experience, 36 hours spent together is all it takes.

And that 36 hours doesn’t have to be consecutive, says Goldsmith.

Her study of almost 300 college-aged men and women found that it did.

Though not a clear indicator of the exact timing to have sex, Mett’s study did provide a checklist of potential steps partners should take before they get physical.In 2010, Dean Busby, the director of the school of family life at Brigham Young University, did a study which suggested that the longer you delay sex — especially if you wait until marriage — the more stable and satisfying your relationship will be.To be fair, Brigham Young University, which funded Busby's research, is owned by the Church of Latter-day Saints, and they have some thoughts when it comes to sex and marriage.“I remember the first night, I was telling him about my difficulty with monogamy,” she says.“I don’t know why I felt the need, but it must have been on my mind a lot.” In almost every relationship she’d had, she’d found herself cheating, though she didn’t know if this was a character flaw or a problem with the conventional system. “I was just trying to get into your panties,” he says to her, laughing.That emotional connection is one of the key elements of any relationship, Toni Coleman, a psychotherapist from the Washington, DC, area, told Business Insider.