Today, he is in a happy relationship with Gwen Stefani, who announced her divorce from husband Gavin Rossdale not long after.
For the first time ever, Stefani opens up about the moment she found out about Shelton's divorce and how it affected her.
She stopped by The Howard Stern Show to discuss Shelton's heartbreaking reveal to The Voice team.
"I was in shock," she said. "I felt like he was exposing me. I just couldn't wrap my head around it. I didn't want anyone to know what was going on with me...I had this huge weight on me and nobody but my parents and obviously everyone involved knew."
Over time, Shelton confided in Stefani more and more, which made her want to reveal what was going on in her personal life, since he was going through the same thing.
"It was during that time, he came up to my chair...I never saw him look so upset. So then I was like, 'I gotta talk to you.'," she said.
Their shared heartbreak turned into a close friendship and support system, and then, ultimately, a relationship.
Stefani said she thinks it was "just unbelievable that God would put us in a position to have each other at that moment, in the same exact moment".