So Facebook knows you're in a relationship, right? Even if you don't tell FB who it is , the scary part is Facebook knows which friend you "heart". FB had developed new algorithm that can also predict whether or not that relationship will last.
Facebook Engineers and some computers geeks that I think has no Girlfriends calculating using a mega load of 1.3 million data from Facebook users who met three criteria.
The Facebook geeks used the data to come up with some new metric called "dispersion" measuring overlap of two people's mutual friends. The criteria are: 1. at least 20 years old. 2  listed their relationship status as married, engaged or dating and 3. had at least 50 friends.  

Facebook is no Ms Cleo

I'm not really sure how they measure it but I'll give it a try to explain it using a "woman". 
In a relationship with high dispersion, a woman would be connected to all of her boyfriends’ closest friends, and he to hers, but those friends would not be friends with one another. In a relationship with low dispersion, by contrast, those mutual friends are more connected to each other. Did you get it?
Ok, Facebook's 40 year old Virgins found that highest dispersion comes from family members, also with romantic partners. So if you look at the factors like age, gender and where the losers live, this algorithm could narrow this down to the most likely boyfriend/girlfriend with 60% accuracy.  Ok, so it will not set the world on fire and doesn't seem like great odds, but think about it,  if we look at the minimum number of friends say 50, you would have a whopping 2% chances of nailing it randomly. 

Not impressed? 
 This is the best as it gets , at least you are aware. 
Particularly intriguing is that when the algorithm fails, it looks as if the relationship is in trouble. A couple in a declared relationship and without a high dispersion on the site are 50 percent more likely to break up over the next two months than a couple with a high dispersion, the researchers found. (Their research tracked the users every two months for two years.)
Check this paper out,  from ArXiv  (another geek), he argues that having high dispersion can lead to successful relationships and by widening each other’s social worlds while maintaining their own circle of friends. If this make sense to you. I'm gonna say you don't really care if Facebook starting using this metric. But I'll say it is live so it is too late for you FB owns you.
photo credit: WadeB via photopin cc