Amy Nuttall reportedly became suspicious of her husband Andrew Buchan after seeing cosy social media snaps of him and co-star Leila Farzad.
The Downton Abbey star, 40, has allegedly been left heartbroken after the Broadchurch actor left her for his co-star, after they met on the BBC series Better.
Now, sources are claiming that Amy grew concerned that Andrew was cheating after social media snaps her husband and Leila appeared a little too close for comfort.
The star then confirmed her fears when she discovered Andrew had been staying in a hotel close to their home - while claiming to be away working on location - and that he had purchased racy lingerie in a size that was not her own.
A source told The Sun: 'The penny started to drop over a period of time. He was away a lot, which wasn't unusual because of the nature of his work, but at one point Amy realised he had been staying in hotels very near to home — and wondered why.
What's going on? Amy Nuttall reportedly became suspicious of her husband Andrew Buchan after seeing cosy social media snaps of him and co-star Leila Farzad (pictured)
Devastating: The Downton Abbey star has allegedly been left heartbroken after the Broadchurch actor left her for his co-star after they met on the BBC series Better
'As time moved on, there were some tell-tale signs that he had become close to Leila — just something in his mannerisms and in their social media posts together.
'But the final straw was the lingerie — that's what clinched it. Amy just knew instinctively that it wasn't meant for her.'
Leila recently shared a gushing Instagram post paying tribute to Buchan for 'holding her up and wiping away her tears,' alongside a snap of them filming their new drama.
Alongside a montage featuring the entire Better cast and crew, she wrote: 'This lot. Couldn't and wouldn't happen without them. Big up the Better team who wiped my tears, held me up, fed me crumpets and made me smile.
'Don't have pics of everyone but this gang got me through! We made a show, it's NOT a Happy Valley replacement but a morality tale which should make you think.'
On Tuesday, Nuttall was pictured for the first time since it emerged her husband has walked out on her and their two children.
The Downton Abbey star, who has been left so 'crushed' by the end of her marriage that she has been crying almost every day, struggled to raise a smile as she ran errands in Buckinghamshire.
Speaking to MailOnline about the split, Nuttall fought back tears and confessed: 'I can't talk about it. I'm sorry, I can't say anything.'
United: Earlier this month, Leila took to social media to share a gushing tribute to Andrew in a montage featuring the Better cast and crew
Happy: She shared a caption lauding her co-stars, including Buchan, for 'wiping away her tears' and 'holding her up'
Rumbled: Amy's fears Andrew was cheating were confirmed when she discovered he had been staying in a hotel close to their home, and had purchased underwear in a size that wasn't her own
Co-stars: Buchan plays well-connected criminal Col alongside Leila's corrupt police officer, Lou, in the crime drama Better, which was first screened on BBC One in February
Crestfallen: On Tuesday Nuttall was pictured for the first time since it emerged her husband has walked out on her and their two children
New love: Broadchurch star Buchan is said to have left the family home over Christmas and moved in with Leila Farzad, after meeting while working on the BBC series Better
Sources close to Nuttall say that she has been supported by her close friend Joanne Froggatt, who used to live close to her and Buchan.
One friend said: 'It has broken Amy, it has been so dreadfully sad to see.
'She got wind that something was going on and she knew she had to say something so she confronted Andrew about it. It must have been the most difficult thing Amy has ever had to do.
'Now she is getting used to life without him and it is really hard. Luckily, she has some great friends around her who are supporting her every step of the way.
'One is Joanne and only a few years ago she split from her husband but she has got through and come out the other side.'
As well as starring in Downton Abbey, the women also appeared in both series of ITV drama Liar together in 2017 and 2020.
Her friends told MailOnline that the split left the actress 'crushed' as she attempts to rebuild her life.
One said: 'It's been very hard for Amy. She's been crying virtually every day since it happened and she's struggling to cope with things. She can't even bring herself to talk about it as she's still trying to make sense of it all.'
Another friend added: 'Amy and the kids have been hit very hard by this, as you can imagine. They are all crushed. One minute they were living an idyllic family life in a beautiful house and the next, Andrew walks out on them.
'I've seen Amy a few times and when I do, she just bursts into tears. She's been doing a lot of crying and is still grieving the end of the marriage.'
A close family friend told MailOnline: 'Amy and the whole family are devastated by what has happened.
'Her parents are really upset by this as is everyone. 'People are very angry at Andrew by what he's done. 'We just did not see this coming. 'It's a massive shock.'
Former flame: Leila was previously married to husband James, with the pair tying the knot in 2013, after being friends for six years. They have daughter Allegra, born in 2014
Amy alluded to their split with cryptic social media posts over the last few months.
The day after Valentine's Day she shared a pointed post that read: 'I am not impressed by money, social status or job title, I'm impressed by the way someone treats other human beings.'
Days before she shared pictures from a holiday, which featured no sign of Buchan but one image with a female pal and a cute snap of herself holding hands with two children.
She captioned the images: 'Holidays with my favourites.'
In another hint that she was going through a tumultuous time, Nuttall shared a selfie drinking a cocktail at the beginning of the month, penning: 'When a pornstar martini makes life a bit better.'
At Christmas she shared a solo snap posing in front of her tree as a follower asked: 'How are you and the kids ? Xxxx'
Buchan is best known for roles in Broadchurch, The Fixer and Garrow's Law - and more recently played Matt Hancock in Kenneth Branagh's Sky political drama This England.
He landed his first big role in Jane Eyre in 2006, and also starred opposite Matt Smith in Party Animals the following year.
Meanwhile, Nuttall found fame after joining ITV soap Emmerdale in 2000 at the age of 18; she played Chloe Atkinson for eight years before leaving the show to pursue a music career.
Former boyfriend: While on Emmerdale, Amy dated co-star Ben Freeman for more than four years before the couple separated amid claims he had cheated on her (pictured on the show)
While on the show she dated co-star Ben Freeman for more than four years before the couple separated in 2004 amid claims that he had cheated on her.
It was reported by The News Of The World that Nuttall discovered Freeman had cheated on her, with a source saying: 'She found out a few weeks ago that Ben had been playing around behind her back but when she confronted him he denied it.
'At first she believed him but then she discovered that he had been calling this girl repeatedly and sending her text messages.
'She found his phone bill and called the girl up. It took a lot of guts but she wanted to know the truth and the girl admitted what had happened.'
In a 2003 interview, while she and Ben were still dating, Amy said she would 'never dream' of chatting up someone else's partner.
She told The Mirror: 'The girls don't make me jealous because I'm very secure in my relationship with Ben, but I do think it's rude. I would never dream of going up to someone else's boyfriend and trying it on.'
More recently, Amy played Ethel Parks in BBC period drama Downton Abbey, with her character losing her job at the sprawling Downton estate after having an affair with a serving officer.
