It has been more than 40 years since Joan first saw Ken rifling through a bin outside her bookstore, homeless and desperate for food.
Together, they have weathered the loss of Joan's husband, mental and physical health problems, and finding Ken a home.
Now both well into their 80s, they have decided to take their relationship to the next level - tying the knot in a ceremony tomorrow.
Joan Neininger, now aged 88, first met her 89-year-old groom-to-be Ken Selway in 1975 when he was hunting for scraps, and took pity on him.
She made him sandwiches and cups of tea, and over the years friendship blossomed - and, after the death of her husband Norman, love followed suit.
They now live together at a residential home in Gloucester, and will be wed on Joan's birthday - four days after Valentine's Day.
Joan said she ended up proposing to ensure they could be placed in a home together - making the most of the "little bit of a leap year" left last year.
It has not been an easy road for the couple, having spent years battling Ken's schizophrenia together to get him back on his feet again.
She found him places he could stay, but he often - for various reasons - refused to go, or found himself unable to stay for long.
Born in London and evacuated to Wales, Ken became homeless after the Welsh man he saw as a father died, and his natural mother could not cope with his mental health problems.
He moved to Gloucester to search for relatives of his evacuee father, carrying with him only a fossil he had once mined, a radio, a few personal items and a clean set of clothes.
Joan said she had noticed how, despite his situation, he always looked smart - his trousers with the crease properly pressed into them.
Their relationship has always been celibate, Joan said - though Ken said he believes they have shared a kiss once - but they share a deep bond, peppered with laughter.
"He's got the nature that I want to maintain," she said.
"He's kind, he's good to everybody. He's ever so kind. He is a lovely person."
Joking, she added: "I know he's vile sometimes - I could knock him on the head. He does wind me up a bit, and he winds other people up sometimes too.
"But fundamentally, if everybody was like Ken, it would be a wonderful world."
For Ken's part, he described his bride-to-be as a "godsend".
The couple will be wed at Cinderford registry office.
- Video report by ITV News west of England correspondent Rupert Evelyn: