"They are absolutely devastated and struggling to come to terms with what has happened," McLeod said.
"I have lost my best friend, the best father to my boys and the most amazing, kindest, positive and adventurous person I have ever known."
Her husband was extremely safety conscious and was a strong swimmer, McLeod said.
Her friends Maria Mariotti and Rita Pontes said McLeod was "deeply in love" with her husband.
Mariotti and Pontes founded Conscious Kids, where McLeod has worked as a parent helper and was set to run programmes this week.
Her birthday was on Saturday, founders Rita Pontes and Maria Mariotti said.
"On Thursday [Leslie] dropped the kids off to the programme in Little Shoal Bay. He left her and he said, 'Relax, we're gonna have a good lunch and celebrate your birthday'. Before that he was going for a swim," explained Mariotti.
She said he then messaged McLeod to tell her what time he was going and what time he would be back.
"So when Laura didn't hear back from him she went straight to [the bay] and around 2pm called the police."
The pair have set up a Givealittle page for the family to help defray funeral expenses and take care of the two boys.
Gelberger was a teacher at Westlake Girls' School and the family's sole income earner. The Givealittle page has raised more than $17,000 in one day.
"We just want to show how Kiwis can gather around in such a sad moment," Pontes said. "We're both from different countries and we know ... it is really hard for foreign people to have support."
McLeod is "the most amazing parent" she added. "She is a beautiful woman and she had a lot of love for Leslie. She had his picture in her wallet, she was deeply in love with him.
"The whole family really love the outdoors - they are really friendly and lovely."
Gelberger's mother, Judith Kopacsi-Gelberger, has told Fairfax she couldn't believe the crew didn't see her son in the water - as she believes he was wearing a bright pink swimming cap.
Her son phoned her at home in Ontario before setting out for his swim on Thursday morning.
"My husband asked him 'is it good weather for a swim?' And he said, laughing, 'any day is a good day for swimming'," she told Fairfax.
That was the last they heard, Kopacsi-Gelberger said. Gelberger's distraught wife called them on Thursday night after he did not come home.
A passing commuter ferry found Gelberger's body on Friday in Mairangi Bay.
Gelberger's mother was afraid his wife and children may not be able to stay in New Zealand after his death, as the family was applying for residency through his work.
McLeod's mother had flown to New Zealand today, Mariotti said.
Ports of Auckland chief executive Tony Gibson yesterday confirmed one of the company's boats was under investigation. The company was co-operating fully with the police to help them to determine what happened.
Gibson said "I am extremely upset that one of our pilot boats may have been involved in the death of a swimmer. I understand the pain this will have caused and I offer the family and friends of the swimmer my deepest sympathies for their tragic loss."
He could not comment further until the investigation was concluded, which a police spokeswoman said would take some time.
