"When things start to get tough for her I will listen and give some voice of reason, but most importantly I will reassure her. She doesn't need me to fix what is upsetting her," he continued.
"Sam, seeing you grow from a beautiful, caring yet fragile girl into a fierce, strong, gorgeous woman has been so special.
"I'm very proud of you. How far you have come in your personal and professional life is inspirational. My life is forever better with you in it," Dave said.
Sam also acknowledged the challenges faced by Dave and her family when supporting her through mental illness.
"Supporting a loved one through mental illness can be extremely challenging," Sam shared.
"It takes great strength to sit in the darkness alongside the person you love. It takes even more strength to hold up a torch and provide light when darkness is all they can see."
Adding of Dave's essay: "His words are so true, they brought a tear to my eye."
Mental health advocate Sam has been open about her own struggles with mental health in the past, speaking honestly about her rocky road to Summer Bay.
Last year, she told fans she wanted to be open about, "the struggles my relationship has due to my ongoing mental health battles and how we're now the strongest we've ever been. I hope sharing my story brings strength and light to others".
She raises awareness on her Believe by Sam Frost website, which she runs alongside her sister, Kristine.
If you or anyone you know is struggling, contact Lifeline on 13 11 14 or visit Lifeline.org.au