The fight ended this week after Yasmin Nakhuda decided against pursuing her appeal against a judge's decision to put Darwin in the care of Story Book Farm Primate Sanctuary.
Nakhuda said the steep cost of a legal challenge with little chance of success coupled with the "crushing pain" of separation had left her with no choice but to abandon her highly publicized quest.
"We did what we can possibly humanly do as his parents," Nakhuda told The Canadian Press Friday.
"He was to us as a human child, and we loved him."
Still, she said, she had no regrets despite having now lost the fight, and endured humiliation and accusations that she had abused Darwin.
She also said she spent close to $250,000.
"If I had to do it again, I'd do it again," Nakhuda said.
"His family he was raised with is us."
In its own statement, the sanctuary based in Sunderland, Ont., said it was pleased the tug of war was over and that it had now assumed permanent care and ownership of the furry critter.
Darwin sparked a social media frenzy when the infant Japanese macaque escaped from a crate in Nakhuda's car parked in an Ikea parking lot in Toronto in December 2012.
Images of Darwin, dressed in a shearling coat, as he wandered around alone quickly went around the world.
Animal services seized him and sent him to Story Book, prompting Nakhuda to sue the sanctuary in an effort to get him back.
Last September, an Ontario Superior Court justice ruled that Darwin is a wild animal and that Nakhuda's ownership ended with his escape from her car, sparking her now aborted appeal.
The judge also ordered her to pay $83,000 in legal costs, something she has done, said Kevin Toyne, the sanctuary's lawyer.
Nakhuda, a real estate lawyer, said she had pursued the case because she loved Darwin and could not stand the thought of his spending the next 30 years in a "jail cell."
"All we can hope is that the sanctuary will show compassion by allowing us to see Darwin and give him the warmth of hugs that Darwin craves and needs for his proper development," Nakhuda said.
"Somehow, deep in my heart, I believe that Darwin and I will still be reunited through the power of love."
Sherri Delaney, founder of the sanctuary, said Darwin's story had focused needed attention on the sale of exotic animals as pets in Canada.
"Unfortunately, Darwin was imprinted by humans in his early and formative months which rarely bodes well for a monkey," Delaney said.
However, he has slowly been learning to be more monkey than human, and has grown in size and confidence, now weighing about 11 pounds — just under half his expected weight as a fully-grown macaque.