AceShowbiz -

Gwen Stefani is leaning on her new love Blake Shelton amid Gavin Rossdale cheating rumors with their nanny. The "Sangria" hitmaker has been "a huge support" for the "Hollaback Girl" songstress.

A source close to Gwen tells E! News, "Gwen is feeling the best she has felt in a long time despite all of this nanny stories circling. Blake has been a huge support system to her not only at work but also on their personal time. They both have been helping each other, really. They have both been trying to stay centered."

The source goes on to say that Gwen and Blake's relationship was a longtime coming. "They always had a thing for each other since The Voice started. They would always joke around and playfully flirt, [but] they never took it to the next level though while they were both married," the source explains.

Gwen opted to end her marriage to Gavin after she found out he was cheating on her with their nanny. "Gwen has known about the Nanny for a few years," the source shares. "Gavin and Gwen lost their spark about a year ago for each other, thinking maybe another kid would draw them close. But really, [it] just brought them further apart. Gwen wanted to try and make it work but in her heart she knew that she could not get past the betrayal Gavin has brought her."

The "Baby Don't Lie" songstress had tried to prevent her children from the news of Gavin's adultery. "She was more upset that he would do that to their kids. Her mind started to focus way more on the kids than him," a second source says. "Gwen didn't want the news about the nanny to get out for the sake of her kids. She really wanted to protect them and not have them go through knowing this went on with their father and someone that she trusted."

The former nanny "is no longer working for Gwen and Gavin, but Gavin is in contact with her, checking up on her to make sure she is OK," according to the second source.