Davina and the former Pet Rescue presenter decided to split after years of counselling.
A source said: “Eventually the time comes when you have to accept it’s not going to work.”
Davina laid bare her marriage turmoil a day before announcing it was over, admitting: “I have made so many mistakes in my life.”
The former Big Brother presenter said she was looking to leave her past behind — before fans knew she had split from Matthew.
Davina shared a motivational quote with her online followers on Friday which said: “Every morning we get a chance to be different. A chance to change. A chance to be better.
“Your past is your past. Leave it there. Get on with the future part.”
Davina added on Instagram: “I really know about this one. I have made so many mistakes in my life. But there is always a new day.”
Last night she confirmed she had split with Matthew, father to her three children, after 17 years of marriage.
She said: “I am very sad to say Matthew and I have separated. Our amazing children are our number one priority.”
Davina previously talked about going to therapy with the former Pet Rescue presenter, which she said last year had been “brilliant”.
A source said: “This is a devastating time for Davina. She has been very open about how hard she has worked to save the marriage for so many years.
“But eventually the time comes when you have to accept it’s not going to work.
“They’re at that stage now and their primary concern is for the well-being of their kids who they adore more than anything else in the world.”
Davina’s first marriage to Andrew Leggett ended after a few months in 1997. She then met Matthew by chance while walking her dog on London’s Clapham Common.
The couple married in 2000 but three years later they were attending counselling.
She said later: “It was the best thing we’ve done. I’ve recommended it to a lot of friends.”
Davina was also open about other aspects of their relationship, once revealing she found a naughty message to Matthew from another woman.
She recalled: “I checked my husband’s Facebook page — never do that! There was a flirty message from someone saying, ‘I hear you’ve split up from Davina’.”
She said she confronted Matthew who told her he had not replied to the message and never would.
And in 2015 she said she kept her husband satisfied in bed so he would not stray.
She said: “Matthew has strong views on underwear. You must keep your husband satisfied in the bedroom department even if you’re absolutely exhausted. Otherwise he will go somewhere else.”
The couple’s career paths changed dramatically over the course of their marriage — with Matthew quitting TV to run a travel business while Davina became the most popular female presenter in Britain.
Their daughters Holly, 16, and Tilly, 14, and son Chester, 11, all have September birthdays because she did not want to miss hosting Big Brother.
She told Kirsty Young on BBC Radio 4’s Desert Island Discs: “I love Big Brother so much and the idea of someone else presenting it was ‘over my dead body’.
"So I said to Matthew, ‘We are not trying for a baby until after December’. So there we are, three birthdays in September.”
The couple renewed their vows in 2015, when she said: “I’m very lucky, because as far as I know I’ve married a really faithful guy.
"When I think of Matthew and me in our 70s I see us on a world cruise with entertainment every night!”