Ellison, 34, passed away in May 2015, shortly after being diagnosed with breast cancer for the second time.
The documentary follows Ferdinand on a journey as he explores how bereaved parents attempt to come to terms with loss and mould new lives for themselves and their children.
“This is one of the only things we are going to go through where I don’t have answers for [my kids] and it’s worrying and daunting,” Ferdinand said.
“When my kids don’t speak it’s difficult,” Ferdinand continued. “I think: ‘What are they thinking?’ I’m desperate to know but I don’t want to scare them.
“I want the best case scenario and the only way I see it happening is to ask them questions. And I do need help, I know that.”
The documentary followed Ferdinand spending time with his kids and showing how he speaks to them about his wife.
In one part of the documentary, his daughter Tia asks where her mummy is.
“Remember I told you before, we buried mummy in the cemetery?” he replied. “Her spirit went straight into the stars and the star you can see is where she went.”
The footballer discusses how he doesn’t think he has grieved properly or given himself time to sit down and go through everything that happened.
His wife passed away in less than 10 weeks after being diagnosed with cancer for the second time.
Since she passed away, a family friend Sandra has been there every step of the way helping him with the kids.
“Sandra has been with my kids since they were born,” he said. “It’s made the process easier knowing that there’s that comfort in my house with the kids because they are comfortable with her.”
Sandra said she keeps the children in routine as much as Rebecca did, preparing breakfast, polishing shoes and trying to keep things similar to how it used to be.
At a later point in the documentary, Ferdinand met with Jigsaw South East, a charity supporting children through the loss of a loved one.
“I don’t want to scare my kids saying the word therapist, especially with the two boys,” the dad said. “Anything that sounds sad, they don’t want to do. Part of me thinks the kids are ready, but I don’t know if I am yet.
“They’ve had a little bit of therapy from a lady at school, but my oldest boy is difficult to work out. I worry about all of them.
“I can’t get nothing out of the two boys especially. I want something to help them to talk and give me something so I know they are alright, because I don’t know.
“We sit around the table at breakfast every morning, but they talk about memories not feelings.”
Near the end of the documentary, Ferdinand set up a memory jar with his children where he gave them all a piece of paper to fill in a memory about their mum.
It encouraged his boys to ask questions about their mum, and where they first met.
“I love doing this, I’m going to do this every day,” his daughter, Tia, said.
‘Rio Ferdinand: Being Mum And Dad’, is on BBC1 on Tuesday 28 March at 9pm.