It comes as Ansell gave an exclusive interview to 5 News as part of their special program ‘Vanished: Where is Nicola Bulley’.
The 45-year-old mum of two went missing on Friday, January 27 whilst walking her doing to St Michael’s on Wyre.
However, Ansell shared that he is “convinced it’s not the river.”
Telling 5 News: “We’ve always been very careful that we don’t want to say, ‘oh, we think it’s that’, and then push that when it might not be.
“The most obvious thing, of course has always been the river. It’s always been my gut instinct and her sisters, and family that, that isn’t the case.
“Extensive searching, as you know is probably well aware has gone on in that river.”
Police have discounted foul play and are treating the incident as a missing person inquiry, believing that Ms Bulley has fallen into the water.
But police say they are still keeping an “open mind” and have been appealing for information.
Focus of the police search on Thursday switched from St Michael’s to around 10 miles downstream where the river empties into the sea at Morecambe Bay, with police patrol boats and rescue boats spotted on the river and in the bay.
Nicola Bulley’s partner says family will never lose hope
Speaking to Dan Walker, an emotional Ansell said Nicola’s family have been going through “unprecedented hell.”
Saying: “hope and that positivity in me are stronger than ever, and I’m never, ever going to let go.
“Nikki would never give up on us ever. She wouldn’t give up on anybody. And we’re not going to ever give up on her, we’re going to find her.”