A relationship between two business partners is often likened to a marriage. But for Bill and Melinda Gates, the two relationships are one in the same. The cofounders of the Bill & Melinda Gates Foundation appeared at the TED 2014 conference in Vancouver, Canada, Tuesday night to talk about their work at the organization. 

"Because we built this thing together from the beginning, it's this great partnership," Bill said. "I had that with Paul Allen in the early days of Microsoft. I had it with Steve Ballmer as Microsoft got bigger. And now Melinda, in even stronger equal ways, is the partner." 

The two started the foundation, which is now one of the largest private foundations in the world, in 1997. The organization focuses on global health as well as providing aid to those living in extreme poverty both in the U.S. and abroad. Melinda was largely running operations there until Bill decided to completely transition out of Microsoft in 2006. The two have been equal partners at the foundation ever since.

It hasn't always been a cinch, mostly because the existing staff had initially had reservations about working for a married couple when Bill first came on full time. But Melinda said their worries eventually faded.

So how has the couple made it work for the past eight years? Melinda said the key is spending a lot of time working on separate projects. But they always know that when they join up again, they'll share a mutual interest in what the other has learned. 

"Whether it's about women or girls or something new about the vaccine delivery chain, or this person that is a great leader -- he's going to listen," she said. "And he knows when he comes home, even if it's to talk about the speech he did, or the data or what he's learned, I'm really interested." 

What's more is that they're hardwired to take different approaches to each project.

Generally, Bill applies data and Melinda applies intuition. He has taught her to look at the research and then go out into the field and see if reality matches up with the findings. "And I think what I've taught him is to take that data, and meet with people on the ground to understand, can you actually deliver that vaccine?" she said. 

"I think it's been a coming to, over time, towards each other's point of view," she said. "And quite frankly, the work is better because of it."