"Karissa has stood by me since we first met in 2004. We have shared plenty of great times but more importantly she has helped me through some of the toughest moments in my life, especially this past year. After giving it our all, late last year we made the tough mutual decision to move on separately," Fanning said at the time.
Fanning's year only got worse as he was famously attacked by a shark at a competition in South Africa — an event that left him suffering from post-traumatic stress disorder.
To cap his year off his older brother Pete, 43, died of an enlarged heart. It was the second brother Mick had lost after a car crash took the life of Sean in 1998.
"That was the one that just floored me. I was like 'what else? What else can be taken in a year?' At the end of 2015, I just hit rock bottom," Fanning said.
"I felt like I had nothing to give, nothing to give myself, or to the people around me, or to family or friends. I just didn't see a way of coming back.
"I've never felt that empty before, I just lay in bed, did nothing, wouldn't leave the house."
Fanning stopped competing full-time and travelled the world on a wave-seeking and soul-searching mission. It was in Alaska he made an important step forward in his recovery.
"I walked to the top of this hill and looked over this beautiful landscape and I just remembered my brothers and felt tears pouring down my face," Fanning said.
"It wasn't sad tears, I was smiling and I was just like, 'okay that's one step'. That was the start of bringing myself back."
Better times were on the horizon. In 2017 he went public with new girlfriend Breeana Randall, his now fiancee and the mother of his newborn son Xander.
"Yesterday was one of those incredible days!" Fanning wrote the day after he proposed. "Breeana and I went to shoot some baby announcement photos and then this happened! This beautiful woman has stolen my heart and I'm so excited to create a beautiful family with her. Bub is due in August. So excited to start this new chapter with a person I truly admire and love."
They welcomed Xander earlier this month and Fanning, 39, is loving being a dad and wants more kids.
"It's incredible," he said of fatherhood. "Just the love and care that you can give to a human, its wild. So mind-bending."