In an exclusive blog for the Daily Mail, the actress has given an insight into the strain that losing a child can have on a marriage, giving a detailed account of how loss impacted her relationship with husband Jim Murray.
The Broadchurch star detailed how one of the biggest hurdles for two parents experiencing grief is the way different people react in that situation, admitting that she and Jim weren't able to comfort each other 'in the correct way'.
Sarah said, 'Such an incredible loss inevitably puts an enormous strain on a relationship because people grieve in different ways.
'It would take the most emotionally mature people to be able to cope in that situation, and to comfort one another in the correct way. I can only say now, eight years later, that I'm not sure we were able to do that at the time.'
Sarah revealed the couple made mistakes in trying to be there for each other, but that ultimately it was their charity work that kept them together.
'The pressure of grief is such that either you end up separating or, miraculously, you don't. Jim and I have remained together despite some terrible, terrible times.
'We have made mistakes and done things that don't work for each other – and you either end up together, or you don't. I think if we hadn't created a charity, the Murray Parish Trust, in memory of our daughter, then things wouldn't have worked out so well for us.
'It has given us something to focus on and it has most definitely been good for our relationship.'
In some of their darkest times, the 48-year-old star admitted that she was worried the pair would 'drink ourselves to death'.
'After Ella's death, we went to Cambodia and Vietnam to do voluntary work in orphanages. It was either that or drink ourselves to death in the pub. And – harsh though it might sound – we needed to escape the sympathy that enveloped us in Britain.'
By trying to help others the showbiz couple were brought closer together.
'Doing these things has helped bring Jim and I closer together. Certainly it has brought a positive out of a negative.'
Ella-Jayne was diagnosed with a hole in her heart while still in the womb and after being born five weeks premature she spent a month in intensive care. At eight months old, she tragically passed away at home.
Since her death, Sarah and Jim have done various charity work and set up the Murray-Parish Trust in Ella-Jayne's memory.
Sarah has spoken openly in the media about losing her daughter and the incredible work she has been doing. Last year the couple appeared on This Morning to talk about their plan to build a trauma centre in Southampton, to repay the hospital for the care that their daughter received.
The husband and wife, who also have a seven-year-old daughter Nell, launched the campaign #2MillionSteps, which aims to match the £2 million given by the government to pay for a new trauma centre at Southampton University hospital.
Speaking about the campaign, Sarah said it was the 'incredible' treatment given by the hospital staff that made them want to give something back.
'She was in the paediatric intensive care unit which was awe awe-inspiring and the people that worked there were incredible. That's why it was so important to Jim and I when Ella-Jayne passed, that we gave back to those people who helped us through such a traumatic, desperate time. And what we're going at the moment again is trying to give back to them', she said.
Sarah and Jim hope the new centre will be on the same level as Great Ormond Street Hospital, covering nine counties and will stop children and adults sharing and accident and emergency wing.
'It's a way of making something really quite awful better. Every time we raise money, every time we do something that makes difference to the hospital or the south of England in its entirely makes Ella-Jayne and our pain worth it,' she added.
In a earlier interview with The Times, Sarah said that despite the heartache there have been moments of 'euphoria' at having known her baby at all.
Describing the period as 'hell', Sarah admitted that though a devastating experience she's proud of the work it inspired their family to do.
The actress, 48, said that initially it was hard for the pair to see the light at the end of the tunnel.
That's when they took action and began to take as many positives out of their situation as they could. Their interest in charity work began after taking a trip to Cambodia, where they took part in hard labour for a month.
Sarah also revealed that she experienced one of the best moments of her life when Ella-Jayne had taken a full bottle, just hours before she passed away. 'Most people look at us like we're mad. "You found complete happiness watching a baby take a bottle?" But we did.
'It was one of the most joyous moments of my life. And it was only that joyous because of the hell we'd experienced prior to it.'