What we learned about love & sex in 2012

The best bedroom accessory might be your music library. A survey by Spotify found that more than 40 percent of people think listening to music is more arousing than touch during sex. And the tunes that survey respondents found the most satisfying? Anything Marvin Gaye.

File this one under, um…seriously?! According to research conducted by U.K. beauty retailer Superdrug, 12 percent of men don't know their wives' birthdays. (How these men are still married—or haven't figured it out by now—we'll never know.) The study also found that, not surprisingly, 11.39 percent of men don't know their wives' bra size and 23 percent are unsure of their dress sizes.

While the Fifty Shades of Grey trilogy was technically released as fan fiction in 2011, the fetish-filled tale of entrepreneur Christian Grey and student Anastasia Steele hit it big in 2012 when the books were released by mainstream publishing houses. As of July, the trilogy had sold 20 million copies in the United States alone and accounted for 20 percent of all adult fiction books purchased. The series also set the record for the fastest-selling paperback of all time, surpassing paperback sales of Harry Potter.

The results of a recent study from UCLA suggested that brides and grooms may need to take their cold feet more seriously. When study participants were asked if they were ever uncertain about getting hitched, 47 percent of husbands and 38 percent of wives said yes. Among women, 19 percent of those who reported pre-wedding reservations were divorced four years later, compared with 8 percent of those who did not report having any qualms about walking down the aisle.

A growing number of adults age 50 and over are choosing to live with their significant other instead of getting hitched, according to an August study in the Journal of Marriage and Family. While these boomers aren't saying, I do, most of them are sticking together: Of the couples who were living together when the study began, the average length of their relationships at that point was more than eight years. And over the course of the eight-year study, only 18 percent of the couples called it quits.

Here's a reason to jump for joy that you're out of your 20s. British social-networking site Friends Reunited discovered that happiness begins at age 33. According to the site's study, 70 percent of survey takers over the age of 40 said they were not truly happy until they'd reached that magical age.

Hooking up has gotten a bad rap over the years but a 2012 study may change that. Researchers found that, on days they have sex, women feel physically satisfied nearly 93 percent of the time, cheered up 67 percent of the time and more attractive 45 percent of the time. These finding were more or less the same for casual sex and committed sex

Scientists began clinical trials on a new birth-control method that can last up to 10 years! Called Vasalgel, the prevention serum must be injected into a man's penis, a procedure that takes about 15 minutes. Vasalgel won't be available until 2015, so men can take these next three years to warm up to the idea.

This year, experts at UCLA led a study to define hypersexual disorder (more commonly known as sex addiction) as a legitimate mental health condition. We'll have to wait until May 2013 to find out if the disorder gets official approval from the psychiatry powers that be—that's when the revised 5th edition of the Diagnostic and Statistical Manual of Mental Disorders will be published.

Well, this is depressing. According to a survey by Match.com, 25 percent of men say they'll marry a woman even if there's no spark. So, what's the motivation for tying the knot? Apparently, these guys are just interested in having someone to cook their dinner, do their laundry and give them convenient access to sex. What year is it again?

Researchers from the University of Texas at San Antonio found that during the week near ovulation, women delude themselves into thinking that the sexy bad boys will become devoted partners and better dads, this according to study author Kristina Durante. Of course, we still like to think that a woman's good judgment can prevail over her hormones.

While it may be tempting to rekindle an old romance, Amber Vennum, assistant professor of family studies and human services at Kansas State University, cautioned against cyclical relationships, where couples split up and get back together. According to her research, people in these second-time-around romances tended to be less satisfied with their relationship and were more uncertain about its future.

Men are often characterized as dragging their feet when it comes to settling down but new research debunks this commitment-phobe stereotype. It turns out that men are apparently more willing than women to move in together, with 46 percent saying that they would expect to move in together within a year of dating, compared to just 26 percent of women who count on cohabitating by a relationship's first anniversary.

According to a survey released by online dating site OurTime.com, 42 percent of adults would reconcile with their partners after an affair. And, women appear to be more forgiving than men are: 46 percent of female respondents would be willing to repair the relationship, compared with 37 percent of males.

We wish. In a survey by the website Good in Bed, 25 percent of respondents said they felt bored in their relationships, with another 25 percent admitting that they felt on the brink of boredom. To end the ennui, 58 percent of respondents said they would be interested in trying something new in the bedroom. Handcuffs, anyone?

What better way to start your day than with a little nookie? Thirty-four percent of Americans say that the optimal time for sex is in the morning, a study released this year found. Sex in the evening came in second at 26 percent, while 23 percent of those surveyed prefer a middle-of-the-night romp.