Lisa is said to be “struggling to accept” the TV presenter’s wish, with their 23-year relationship thought to be on the rocks ever since Ant checked into rehab for prescription drug addiction earlier this year.
Speaking to The Sun, a source revealed: “Ant and Lisa are definitely over. He sees no way back for their marriage.
“Lisa has been struggling to accept it is the end. It is all very sad, especially with all she has gone through this year.
“She was clinging to the hope they could work things out.”
The insider went on to reveal that Ant wants to release an “official statement” in the new year in a bid to “move on”, however, so far Lisa has refused to agree to this.
Despite the reported separation, the pair are said to be on “friendly” terms.
Last week, Ant was spotted looking “anxious” as he arrived in Newcastle for Christmas with his family – away from Lisa.
A source said at the time: “Ant doesn’t feel there is any future in the marriage, and while Lisa is hoping there’s a chance they can turn things around, he doesn’t see how they can.
“He felt it was best he spent Christmas up North with his mum and gave them both some space to think ahead of the New Year.”
Upon his release from rehab Ant praised his wife, admitting that he put her “through hell” as he battled with depression and addiction.
Ant first met Lisa in 1994 when she was in the band Deuce, just five years after he and his co-star Declan Donnelly first found fame in CBBC drama Byker Grove.
The pair tied the knot in 2006.
Yahoo Celeb UK have contacted Ant’s reps for comment.