Robert Taylor, who lived in Lightcliffe with his wife Janet, died while on holiday on April 15 in the Maldives, just before his 65th birthday.
"It's just devastating" said Janet. "Our adopted daughter is ten years old and we adopted her thinking we'd be with her to see her grow up, see her married, but she's not going to get that now.
"He'd done two dives, he was down on another dive and as he ascended his dive buddy noticed there was an issue.
"They brought him to the surface, tried to rescue him but unfortunately he didn't survive.
"He'd been scuba diving for 20 years, it wasn't as if it was a new thing. I think it was something like his 53rd dive, we'd dived all over - Cuba, Egypt, Malta, it was our fourth visit to the Maldives, Kenya."
Robert and Janet were foster carers in Calderdale for 20 years, but before that were kinship carers, which involves caring for people within your friends and family network.
In 2020, the couple were runners-up in a national foster carers of the year competition
"We fostered for 37 years," said Janet. "We felt our calling was to be there for children who didn't have a family.
"People say 'how many children have you fostered?', I have no idea whatsoever but they've all been long term.
"Our eldest two, one is a social worker and the other is a PE teacher, but when they came, at ten and seven, they'd had a terrible childhood.
"It's lovely to see they've changed their lives.
"Fostering was our life."
Robert worked at Clare Hall School in Halifax for 17 years, then went to work for St John's Ambulance as a trainer, from 1997 until 2017, as well as volunteering for the service.
Robert was a school governor for St John's Primary in Clifton, and was actively involved in amateur stage productions, both in school and church.
"He was quite reserved. If he was interested in something he was very passionate about it, like quizzing," Janet said.
"He was always good to have on a quiz team. he just had a had for stuff where you'd think 'how the hell do you know that?'."
Robert is also survived by his sister Joan
Robert's funeral takes place on June 7 at 10am at St John the Evangelist Church in Clifton.