Former political adviser Derek Draper 53, remains in hospital after being admitted with coronavirus symptoms one year ago in March.
ITV documentary Finding Derek featured Good Morning Britain star Garraway, also 53, and the couple's two children, daughter Darcey, 15, and 11-year-old son Billy.
It detailed their experiences during Draper's illness and featured Garraway speaking to people suffering long Covid, NHS staff and other experts.
One scene saw her recall being told by Draper's doctors that he was the most seriously ill person they had seen who remained alive.
After watching the documentary, celebrities rallied around Garraway on social media.
Ben Shephard, Garraway's Good Morning Britain co-star, said he is "so proud" of her as she "continues to surprise, delight, occasionally infuriate but always inspire me".
He added: "Thinking of Kate, her family and anyone who is battling Covid or has lost someone close to them to the virus."
Lorraine Kelly tweeted: "Heartbreaking but such courage, humanity and strength @kategarraway - you are incredible!"
Garraway's now-former Good Morning Britain co-star Piers Morgan described the show as "heartbreaking", as did This Morning's Alison Hammond.
Hammond said Garraway is "amazing".
BBC Breakfast host Dan Walker tweeted: "Really tough watching #FindingDerek Nothing but respect for @kategarraway & the rest of her family."
Singer and TV presenter Myleene Klass said the programme was "utterly heartbreaking".
She added: "@kategarraway you are so full of bravery and courage. Derek has the most incredible woman standing by him x."
Coronation Street actress Samia Longchambon tweeted: "Oh @kategarraway you are so strong of spirit.. sending much love to you and your beautiful family. Here's hoping you all have many brighter days together ahead."
TV presenter Anneka Rice said she was "praying for a happy ending" before the show finished, adding: "You're all so brave and beautiful."
Gloria De Piero, former political editor of GMTV and an ex-Labour MP, said: "So much love for @kategarraway and Darcey and Billy. We miss you Derek."
Tweeting before Finding Derek aired, Good Morning Britain star Charlotte Hawkins said: "It's so heartbreaking, we're all just praying Derek will find a way back. Please watch & send love to Kate & her family."
Garraway had earlier thanked fans for their support.
She said: "Thank you so much for all your lovely comments - your support means so much to me and others."