T.J. Holmes and Marilee Fiebig File for Divorce After His Romance with Amy Robach Is Revealed

T.J. Holmes and Marilee Fiebig are officially taking action to end their decade-plus-long marriage.

The GMA3: What You Need To Know co-anchor, 45, and the powerhouse attorney have filed for divorce after 12 years of marriage, according to public court records.

The former couple — who tied the knot in March 2010 — welcomed their daughter Sabine in 2013. Holmes also shares daughter Brianna as well as son Jaiden with ex-wife Amy Ferson.

News of the filing comes after Holmes was photographed out and about with his colleague Amy Robach in November. A source has since confirmed to PEOPLE that the pair are dating.

"This was two consenting adults who were each separated," the source said of Holmes and Robach, who is married to Melrose Place actor Andrew Shue. "They both broke up with their spouses in August within weeks of each other. The relationship didn't start until after that."

A second source revealed that Robach, 49, had been "going through a heartache and T.J. was very much there for her and helpful, and that is when they started something."

As reports of their relationship surfaced, Holmes and Robach both shut down their respective Instagram pages. The pair have not publicly commented on their relationship, though they alluded to the news days later during a broadcast of GMA3: What You Need To Know earlier this month.

At the beginning of the show, Holmes joked, "You know it's too bad it's Friday, it's been a great week. I just want this to keep going and going and going. Just enjoy it."

Robach laughed as she told Holmes, "Speak for yourself. I am very excited about the weekend, and I'm sure everyone else is too. We all love our Fridays around here — some of us do, at least."

Though news of their relationship surfaced in late November, a TV insider told PEOPLE that their relationship was "widely known" among many GMA staffers. They were even told to "knock off" their flirtatiousness with one another a while back.

"There were so many people internally that were unhappy about it," the insider said. "They were flirtatious."

However, the first source clarified to PEOPLE that a romance only recently blossomed between the close friends once they were separated from their spouses.

"Everyone knew they were close friends and had good chemistry," the source said. "There was a point at which, several years ago, another GMA cast member had sort of made a joke with T.J. about how close he was with Amy and he was very embarrassed. They had each gone through different things and people knew it was a friendship."

"They joked how good their chemistry was, but they shut it down and made it clear they were each going through their own stuff and there was nothing between them," the source added. "She and T.J. just did things together all the time. Her daughter babysat for his daughter. They were open about it. Their lives were intertwined because of work and they were best friends, so when their marriages ended, he was there for her and it was a very natural transition."

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Holmes and Robach were taken off air on Dec. 5 and remain on hiatus as ABC investigates their relationship. The couple will "remain off-air pending the completion of an internal review" with a rotation of anchors filling in on the program, according to a memo sent to staffers.

Robach married Shue, 55, in 2010 at The Lighthouse at New York City's Chelsea Piers. The estranged pair both have children from previous relationships.