Just in time for Valentine's Day, the folks at Happify have culled a bunch of research on what makes — and keeps! — a couple happy. They dug through study after study and, lo and behold, determined that sharing was at the heart of the matter. 

They found that happy couples connect with each other, do things together, and just generally interact more than the unhappy ones. And the results are tangible — to the tune of an additional $105,000 a year in equivalent "life satisfaction" — and gleaned from simply taking walks, trying new restaurants, traveling, and having more sex. Turns out that happiness is a win-win!