Johannah Deakin died on Wednesday morning after suffering from leukaemia.
She had been cared for at University College London hospital since May before being moved to the Royal Hallamshire Hospital, in Sheffield, for the last few weeks of her life.
In a statement issued by Tomlinson’s representative, her family said: “It is with immeasurable sadness that Johannah Deakin’s family said goodbye to Johannah in the early hours of Wednesday, December 7.
“Earlier this year Johannah was diagnosed with a very aggressive form of leukaemia that required immediate and continuous treatment. We respectfully request that the family are given time and space to grieve in private.”
Her husband, Dan Deakin, paid tribute calling her “incredibly selfless” and a “truly amazing mother”.
As well as 24-year-old Tomlinson, she leaves behind six other children, Lottie, 18, Felicite, 16, and two sets of twins, Phoebe and Daisy, 12, and two-year-olds Ernest and Doris.
Mr Deakin said: “She would always look to put other people before herself.
“She desired nothing more than for everyone around her to be happy and loving. She worked tirelessly on numerous charity campaigns, creating memories for many individuals and their families.
“It wasn’t uncommon for Johannah to hear through the media of an individual in need of assistance, and she would immediately make it her objective to get that person what they often desperately needed, and rarely without success.
“These are the things that made Johannah happy and content in life, and all of which for me made her simply the perfect wife and best friend to face each day with.
“I thoroughly loved walking through life with her, and though five years was far too short a time, during that time we had so many lifetimes worth of happiness, adventures, and memories.”
Mr Deakin added: “We would like to send our sincere thanks to Professor Steve Mackinnon and his team at University College London Hospital, where Johannah was hospitalised since May. And, during the last few weeks, Professor John Snowden and his colleagues at Royal Hallamshire Hospital Sheffield.”
Tomlinson, who had been scheduled to make a surprise appearance on the X Factor this weekend, will still perform in memory of his mother, his management confirmed.
Felicite posted a heartbreak emoji on her Twitter account on Thursday night.
Stars from across the music industry sent messages of condolence to Tomlinson including singer Cheryl, who is in a relationship with his One Direction band mate, Liam Payne.
She wrote: “@Louis_Tomlinson my heart breaks for you. I am so sorry. My thoughts are with you and your loved ones at this incredibly tragic time.”
The Wanted’s Nathan Sykes wrote: “Thoughts are with @Louis_Tomlinson today. Heartbreaking news.”
Former Boyzone star Ronan Keating posted on Twitter: “ My Heart goes out to Louis Tomlinson and his family at this time. Heartbreaking.”