Kingston and Apollo Rossdale, Blake Shelton, Gwen Stefani.Photo: Axelle/Bauer-Griffin/FilmMagic

Kingston Rossdale, Apollo Bowie Flynn Rossdale, Blake Shelton, and Gwen Stefani attend STX Films World Premiere of “UglyDolls

A friend in the couple’s circle tells PEOPLE in this week’s cover story, on newsstands Friday, that the No Doubt rocker’s sons Kingston, 14, Zuma, 12, and Apollo, 6, “will have a large part” in her upcoming wedding to the country star.

Shelton, 44, and Stefani, 51 — whoannounced their engagementon Instagram Oct. 27 — first struck up a friendship in 2014 while working together on the coaches' panel ofThe Voice’sseventh season. Both married at the time, it wasn’t until a year later that their relationship turned romantic while they leaned on one another during their respective divorces. (Stefani announced her split from Bush frontmanGavin Rossdalein 2015 after 20 years together just weeks after Shelton and his ex-wife, country singerMiranda Lambert, finalized their divorce following four years of marriage.)

This week’s PEOPLE cover.

Gwen Steani and Blake Shelton People Cover 1/11/2021

As Shelton’s bond with Stefani blossomed over the years, so did his relationship with her three sons.

“From the beginning, Gwen made it clear to Blake that her boys were No. 1 in her life, and Blake always respected this,” says a source close to Stefani. Adds the friend: “He never wanted to overstep and made sure everyone was comfortable with his role in her sons’ lives.”

As Shelton slowly introduced Kingston, Zuma and Apollo to the laidback lifestyle on his Tishomingo, Oklahoma, ranch, where they often spend time fishing and camping on holidays and school breaks, Stefani fell deeper in love.

“Gwen always gushed about how amazing Blake is with the boys,” says the Stefani source. “She feels so lucky that he helps her raise them. His love and guidance is something that Gwen is beyond grateful for.”

RELATED VIDEO:Gwen StefaniShows Off Her Engagement Ring fromBlake SheltonDuringThe VoiceLive Shows

When Shelton was planning his proposal, he knew he wanted Stefani’s boys to be there.

After getting permission several weeks earlier from Stefani’s dad Dennis, as well as her sons, Shelton bought the engagement ring — which WP Diamonds CEO Andrew Brown estimates to be seven carats and worth at least $250,000 — and kept it hidden in his truck.

“I had the ring in the compartment on my door of my truck for about a week,” Shelton said. “[When I was] digging in there looking for a flashlight or change, I kept thinking, ‘Man, somebody’s gonna hit the jackpot whenever I drop this thing out of my truck.'”

Gwen Stefani and Blake Shelton.Steve Granitz/WireImage

Gwen Stefani, Blake Shelton

Luckily, Shelton didn’t lose the ring, and the proposal turned out even better than he could have imagined.

“Gwen was amazed and absolutely not aware the proposal was happening,” says an industry source. “It was a shining point in her life.”

Sources expect the couple’s nuptials to take place in a chapel Shelton built for Stefani on his ranch — the singers gave fans a peek at the special place in their engagement announcement — and for the wedding ceremony to be intimate and emotional.

“It will be smaller with family and only close friends,” says the industry source. “They aren’t rushing it now but do want to marry soon.”

RELATED GALLERY:Blake Shelton and Gwen Stefani’s Absolute Cutest Photos

Gwen Stefani and Blake Shelton’s engagement.Gwen Stefani and Blake Shelton

Gwen and Blake

As they continue to split their time in quarantine between Oklahoma and California, Stefani and her sons are thankful for the respite that Shelton’s ranch offers.

“Blake’s life in Oklahoma is very different from their L.A. life,” says the Stefani source. “They have a lot of freedom there and can do outdoor activities. It’s been such a perfect escape during COVID.”

It’s also provided a burst of creativity for both Stefani and Shelton, whose duets “Nobody But You” and “Happy Anywhere” both went No. 1 after their releases in April and December, respectively. Then on Dec. 15, Stefani earned herfirstVoicevictory with contestant Carter Rubinone week after seeing her new single “Let Me Reintroduce Myself,” reach the top of the iTunes chart following its debut.

“It’s just such a different chapter,” Stefani — who hadn’t released solo, non-holiday music in four years —told Apple Music’s Zane Loweon Dec. 7th. “Life’s gotten so good.”

Blake Shelton, Gwen Stefani.Steve Granitz/WireImage

Gwen and Blake

And now with a wedding on the horizon, 2021 is looking even brighter.

“Gwen didn’t think an engagement would change her and Blake’s relationship because it felt like they were already married, but it has sparked even more happiness,” says the Stefani source. “The wedding has given her something amazing to look forward to in the new year.”

For more onGwen StefaniandBlake Shelton’s wedding plans, pick up the latest issue of PEOPLE, on newsstands Friday.

Melody Chiu

andLinda Marx

Linda Marx

source: people.com