In the fickle game of love, it can often feel like we hear about a celebrity break-up every other day.
But then there are always the exceptions that restore our faith in humanity.
On Tuesday, the wake-boarding pro shared a beautiful beach-side pic with Bindi during a snorkelling trip complete with a heartfelt tribute to his "life adventure buddy."
"Happy Birthday, @bindisueirwin! This will forever be my favourite day of the year. Celebrating the one that I love, my life adventure buddy," Chandler began.
"The one who in her spare time can be found drinking tea, writing letters, and getting flowers for everyone she cares about."
The 21-year-old continued: "Bee, you are the strongest person I know and spread so much kindness every single day. You inspire me to be a better man and I thank my lucky stars for every moment we spend together. I love you. Happy birthday."
During an appearance on Today ahead of her birthday celebrations, Chandler revealed he had "a few surprises" in store for Bindi.
"I won't reveal them quite yet but I did get her a beautiful bouquet of flowers," he shared.
"He got them for me early because every day should be a birthday celebration so that was nice!" Bindi beamed.
Like her parents fateful first meeting while Steve Irwin was performing a croc show, Australia's wildlife princess first met Chandler in 2013 when she took his family on a tour of Australia Zoo in Queensland.
The pair hit it off and Chandler, ever the gentleman, asked Bindi's mother Terri Irwin for her blessing to keep in touch with the star.
Chandler Powell on what he has planned for Bindi Irwin's birthday. Post continues...
After months of writing letters to each other, Bindi and Chandler met up in July 2015 and haven't looked back.
''I've found the one," Weekly cover girl Bindi previously told us.
"I believe there's always someone for everyone and when you find that one, as we have found each other, it's a real blessing and a privilege. We all think Dad would have loved Chandler."
Meanwhile, Bindi's devoted younger brother Bob Irwin, 14, also paid tribute to his sister.
"Happy birthday @bindisueirwin Wow. I can't believe you are 20 today! You have achieved so much and your message of positivity and kindness is so inspiring," Bob wrote next to an adorable picture of the pair cuddling up to a baby kangaroo and an echidna in their world famous khakis.
"Thank you for being the best sister in the world, love you heaps! Today will be so fun," he signed off.
Mum Terri Irwin admitted she was still coming to terms with her darling daughter entering her 20s.
"I think Bindi is just amazing and she goes from strength to strength. She's so much like her dad and just loves wildlife. I admire her greatly. It's really cool that she's just fledged and she's all grown up! I know Steve would be so proud as well," Terri told Today.
The Dancing With The Stars champ will ring in her 20th birthday today with a huge celebration at Australia Zoo, complete with a pink carpet and a croc feeding demonstration in front of thousands of fans.
Steve Irwin would be so proud of his little girl all grown up!