Gwen Stefani and Blake Shelton are the cutest.

On October 3, as the ageless Stefani celebrated her 48th birthday, she received a sweet birthday message from her boyfriend that included a nod to their 2016 duet, "Go Ahead and Break My Heart," which the wrote during the first several weeks of their romance.

"Happy Birthday @gwenstefani!!! Why don't you go ahead and NEVER break my heart!!!!" he tweeted.

"@blakeshelton thank u for saving my life," she responded.

Stefani and Shelton began dating in 2015 and are now acting as a family with Stefani's three sons, 11-year-old Kingston, nine-year-old Zuma, and three-year-old Apollo, all of whom appear to be major fans of Shelton.

“Kingston and Zuma love a bunch of things about Blake, he is a fun guy,” a source close to the couple told Hollywood Life at the end of last month. “But one thing that they really love is watching him on TV. They think that it is super cool and they enjoy watching The Voice to see him on it.”

“They have so much fun with Blake and learn so many cool things whenever they get together,” another insider told the outlet. “The boys have really fallen in love with Blake and have a strong bond with their mother’s boyfriend. They are very much attached to Blake and hope he is around for a long time.”

“Blake has really taken to all of Gwen’s kids and loves to share his passions with them. Besides Gwen, nothing is as dear to Blake as his country music, so to share his own country style of guitar meant a lot to him. It seemed to mean even more to Gwen, though — she was brought to tears as she saw her boys learning from her man,” the source added.