: “To see someone as beautiful as her with this illness is horrific. It's so sad.
"It's extremely, extremely, extremely painful."
Vicky, 63, was diagnosed last year with the same cancer that killed her father.
Despite her struggle, Bobby says they have tried to “keep on laughing” as a couple, who have been together for 12 years.
He has also thrown himself into his work as a "distraction" from what they're going through.
Bobby added: "My best advice for someone in a similar position is that laughter is the best medicine.
"I always remember this quote, 'Don't let the world change your smile - get your smile to change the world’.”
Impressionist Bobby celebrated his engagement to Vicky in December last year with a star-studded party.
At the time, Vicky — the daughter of Wolves and England football great Billy Wright and Joy Beverley of the Beverley Sisters — said: “I’m on cloud nine.”
Video messages were also sent in to Bobby’s fiancée from showbiz pals Sir Cliff Richard, Gilbert O’Sullivan and Lee Mead.
The couple, who have dated on-and-off for 12 years, celebrated, surrounded by family and friends, at The Kings Arms, in Egham, Surrey.
Panto favourite Bobby has three children with his ex-wife, Trudi Jameson.
They split in 2003.
Bobby’s 1990s show A Kind Of Magic pulled in millions of viewers.
He has since appeared in EastEnders, Dancing on Ice and Celebrity Big Brother.