Christina Aguilera's alleged pregnancy was reportedly not planned but new fiance Matt Rutler didn't propose because of the baby news.

The pregnancy "wasn't expected, but it also wasn't unwelcome. They are all very excited though! Christina loves being a mom. They just want a healthy baby," a source told Us Weekly.

Rutler had reportedly been thinking about proposing to The Voice coach for several months prior to actually popping the question on February 12 -- although Aguilera didn't announce she was engaged on Twitter until two days later on Valentine's Day.

According to another Us source, the production assistant had been "working on the ring for over a year" and "he wanted to do something that had meaning for both of them."

Rutler reportedly proposed to Aguilera in tears around 7PM in the quiet backyard of their new, yet still under construction, home. He dressed in a suit, showed the singer a newly-planted Cherry Blossom tree -- which grows her favorite flower -- and then asked for her hand in marriage in a gazebo surrounded by candles and roses.

"She was completely taken aback. She had no idea that he was going to propose then," said the second source. "She was shocked."

After the special moment, Aguilera, 33, was surprised with an engagement party Rutler had planned beforehand.

"It was a great night," the second source told Us.

The couple has been dating for three years. Aguilera met Rutler on the set of her 2010 film Burlesque when she was reportedly in the middle of divorcing ex-husband Jordan Bratman, whom she has a six-year-old son Max with.

Aguilera and Bratman wed in November 2005, welcomed Max into the world in January 2008, split in October 2010, and ironically finalized their divorce on Valentine's Day 2011.

Aguilera starred on The Voice for its first three seasons before taking a break in Season 4, when she was replaced by Shakira, to spend time with her son and concentrate on her music career.

Aguilera returned to serve as a coach for Season 5, but will once again have Shakira fill her shoes for the upcoming sixth edition, which premieres Monday night on NBC.

Adam Levine and Blake Shelton have served as mainstay coaches on The Voice since the show debuted in Spring 2011, while coaches Cee Lo Green and Usher -- like Aguilera and Shakira -- have been taking turns on the panel in recent seasons. However, Green just announced this week he will never be coming back to the reality singing competition.