Nicola Bulley's partner says he '100% knows' the missing mum is not in river as the two-week search to find the dog walker continues.
Paul Ansell has spoken in an interview that will air tonight and says her family are going though 'unprecedented hell' as 'nothing seems real'.
But he says they will not give up hope and he told presenter Dan Walker that he is totally convinced that she is not in the water.
Part one part of the 75-minute special programme 'Vanished: Where is Nicola Bulley?' hits our screens on Channel 5 tonight at 9pm.
Distress Mr Ansell says that the family haven’t given up her - as she wouldn't give up on anyone else.
"What we’re going through now is like unprecedented hell," he tells the presenter.
"But that hope and that positivity in me is stronger than ever, and I’m never, ever going to let go. Nicky would never give up on us ever.
"She wouldn’t give up on anybody. And we’re not gonna ever give up on her like, we’re going to find her.”
The mum-of-two, 45, was last seen walking her dog Willow after dropping her daughters off at school in the small village of St Michaels on Wyre, Lancashire on January 27.
Lancashire Police launched a massive search and were seen combing the river bank, utilising diving teams, search dogs, drones and boats to no avail.
“Extensive searching, as you’re probably aware, has gone on in that river," he told Dan.
"The fact that the divers and underwater rescue team and all that were in that river on the day, and thankfully found absolutely nothing, in the part where you would have to presume is her last known location.
"Personally, I am 100 per cent convinced it’s not the river, that’s my opinion.”
"Because people don't just vanish into thin air, it's absolutely impossible. So something has happened.
"Something has happened. Find out what it is. Find out what it is.
"There has to be a way to find out what happened, there has to be. You cannot, you cannot walk your dog down a river and just vanish into thin air. Something happened that day, something.”
He refuses to point fingers at the police, despite no news two weeks on.
The force are this afternoon trawling underneath a bridge more than seven miles from where the mortgage adviser was last seen.
“I have to categorically say I cannot fault the police in any of this, they have been incredible, and the relationship that we have working on this is still very, very strong, it’s very good," he added.
"So this isn’t any criticism of them at all, I just want to make that clear.”
The bridge is about halfway to the estuary from the village.
Images show specialists in a small boat travelling around and under the road crossing.
It comes as the search has already expanded to the Irish Sea.
Police have said their "main working hypothesis" was that she fell in a river but a body has not yet been found. However, they insist they are keeping an open mind.
