Watch: Kelsey Parker opens up about grief and her first Christmas without Tom Parker
Opening up about her grief on Good Morning Britain, Kelsey said you can feel so many different emotions all at one time.
"You can be happy, you can be sad, you can be angry," she said.
"Obviously there is guilt."
When host Kate Garraway asked what she meant, Kelsey said: "For me there's massive... there is so much guilt and that's what is a theme through the show.
"I have just got a lot of guilt.
"I know that I did everything for Tom. Even still there is just that guilt process of, I've lost him.
"I feel guilty that I'm still here."
Kelsey – who married Tom in 2018 and had two children with him – went on: "I look at my kids every morning and I am guilty that he's not experiencing what I am experiencing with them."
ITVBe series, Kelsey Parker: Life After Tom, will take an unflinching look at the reality of bereavement, confronting death with compassion, empathy and humour.
It will also explore how Kelsey is rebuilding her life with her and Tom's young children.
"I was a bit worried, I was like, can I actually do this?" she said on GMB.
"But for me it's the best thing that I have actually done. Because it has actually been therapy for me."
"It has massively helped me," she added.
Parker was diagnosed with inoperable stage-four glioblastoma in 2020, while Kelsey was pregnant with their son Bodhi.
The couple already had daughter Aurelia, who was born in 2019.
Watch: Kelsey Parker on her non-stop research into cancer treatments to help husband