"Millennials have been shaped by the rise of the internet more than other generations so that has conditioned them to be more open to these kinds of boundary-crossing behaviors on the internet," he said.
"Another possibility is that they're just younger and that's the story here, and as they age and mature they will be more prudent about how they approach the internet. The third possibility here is that they're more likely to be cohabiting couples than married, and we've also seen the data that cohabiting couples are more likely to cross these emotional and sexual boundaries online compared to married couples," he added.
One of the most surprising and concerning finds of the study for Wilcox was that there was a noticeable decline - an 8 point percentage over a 20 year span - of people who said it was "always wrong" to have sex with someone who is not one's spouse.
"This is a worrisome development because we know that support for sexual fidelity in principle and also living the virtue of fidelity in practice are both linked to higher quality and more stable marriages," he said.
Jeffrey P. Dew, an associate editor of the study and an associate professor in the School of Family Life at Brigham Young University, told CNA that one of the findings of the survey that surprised him was that the rate of unfaithfulness in marriage has remained stable over the past few decades, despite increasingly permissive attitudes about marriage and sexuality.
"In terms of the percent of ever-married people who admit to having an affair, that's been stable at about 15% for two or three decades now," Dew said.
"That surprises me. Certainly as a society we're much more permissive and tolerant of people's lifestyle choices, and yet we still find, when it comes to their own behavior, the vast majority would just as soon make sure that their own relationship is exclusive."
Part of the problem of unfaithful online behaviors is that they can be based on a false perception that greater happiness lies elsewhere, Dew said.
"I think even just following an old boyfriend or girlfriend can be problematic because you compare what you think you see online to your own real life, lived experience with your current partner," he said.
"Of course we know that Instagram and Facebook and all those other social media sites - everyone portrays life as this golden, glowing, happy thing, so of course following an old flame online might cause your own current relationship to sour somewhat," he said.
Wilcox said the way people perceive their online lives as being somehow different or separate from their real lives could also be a factor in permissive attitudes toward online infidelity.
(Story continues below)
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"Most of us are probably more considerate and thoughtful about how we treat others in person than when we are interacting with them online, in terms of a disagreement for example," he said. "I think that same spirit of kind of greater orientation towards risk or being less careful also applies to this domain of our online lives."
Jackie Francious-Angel and her husband, Bobby, are Catholic speakers on the topic of relationships and marriage, and are the authors of "Forever: A Catholic Devotional for Your Marriage."
Jackie told CNA that she agrees that online infidelities might be easier to slip into, because people are less careful with what they say online than with what they would say in real life.
"With messaging and texting...you say things there you would never say face to face, because it's so easy," she said.
"Words carry weight and meaning," Bobby added. "We could think, 'well I didn't do anything, nothing actually happened.' We equate cheating with physical activity. But...our words and what we're doing digitally has just as much an impact on our relationships as physical activity does."
Jackie said that a good rule of thumb for couples to consider is whether or not they would be ok with their spouse reading their text messages or social media messages.