A sense of humor is an attractive trait. Evolutionary psychologist Gil Greengross, Ph.D., said there is abundant cross-cultural evidence that shows that being funny makes you a more desirable mate. Especially if you're a man!

"For dating couples, the use of positive humor (for example, using humor to cheer up your date) can positively contribute to relationship satisfaction," Greengross wrote in Psychology Today. "The use of aggressive humor, on the other hand (teasing and making fun of your partner) has the opposite effect. These feelings can fluctuate on a day-to-day basis, depending on each partner’s use of humor."

For long-term relationships, such as in marriages, couples generally share a similar sense of humor. But these similarities are not associated with greater marital satisfaction, nor with longer marriages.

"Perhaps not surprisingly, the research that resulted in this finding also found that couples with fewer children laugh more, compared to couples with a larger number of children."

"In another study, conducted with 3,000 married couples from five countries, both husbands and wives were found to be happier with a humorous partner, but this trait was reported to be more important for the marital satisfaction of the wives than the husbands. Interestingly, both husbands and wives thought that the husband was humorous more often. Regardless, married couples overwhelmingly say that humor has a positive impact on their marriages," Greengross explained.

But what about those moments when things aren't going so well? Humor is a great icebreaker and a social lubricant, but can it also help resolve conflict in marriages?

In one study, researchers observed 60 newlywed couples when they discussed a problem in their marriage. They coded how much humor was used in the conversation and also completed a measure of life stress. What researchers discovered when they followed up 18 months later was quite surprising: in couples that reported high stress, the more the husband used humor, the greater the chance the couple would separate or divorce.

So I guess, timing is everything, guys. Not everything's a joke! But if you get it right, you get it right.