Blake Shelton and Gwen Stefani want to get married, according to a new report ... but there's one major obstacle standing in the way. In a new cover story, People reports that the couple are holding off on getting married because Stefani wants a church wedding as part of her Roman Catholic faith, which "isn't currently possible."

The couple met on the set of The Voice when Stefani joined the show in 2015, and they began dating after both of them went through divorces. Multiple sources tell People that Shelton was "very serious" about their relationship from the beginning, and he thought about proposing early on. But Stefani wants to have a church wedding, and that isn't possible in her faith unless she has her previous marriage annulled, which can be a long process.

Despite that roadblock, the couple are basically living as man and wife now, splitting their time between Shelton's ranch in Oklahoma and a house they purchased together in Los Angeles. Shelton is also very close to Stefani's three sons, and their families have gotten to know each other and are "very like-minded and comfortable with each other."

“It’s definitely headed toward marriage," a friend of the couple tells People.

Shelton recently revealed that he's had a renewal of his own faith since he started dating Stefani. She convinced him to start attending church regularly, and that made him realize that it was time to "turn a page," he tells Nashville's Tennessean newspaper.

“I believe in God now more than I ever have in my life,” Shelton says. “The biggest part of that is just how [Stefani] came into my life and now our relationship. It’s just too weird. If you take God out of it, it doesn’t make sense. If you put God into it, everything that’s happened with us makes sense.”

Country Music Fans Will Love Caylee Hammack!

See Blake Shelton Through the Years