Penning an emotional essay, Bashford, 27, shared his feelings in response to a social media post by Frost, asking her partner what it is like being in a romantic relationship with somebody who suffers from mental illness such as depression and anxiety.
The Home and Away actress wrote: "I asked my partner Dave to write a piece about what it's like living with someone who suffers from mental illness, in hope to help others who might be in a similar situation."
Frost, 30, added: "His words are so true, and brought a tear to my eye".
Responding on the Believe by Sam Frost website, Dave wrote: "The signs your partner is struggling with mental illness are; short-tempered, irrational, emotional, distant and unmotivated".
He added: "The most important thing that I have learnt throughout my relationship with Sam is that I am not a professional and solving her problems isn't what I am there for.
"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 concluded: "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". The couple, who were formerly friends before lovers, began dating since 2017.
Last year, Frost explained how 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".
The beloved-Australian star gained her fame from being the winning contestant on Blake Garvey's season of The Bachelor. Controversially, Frost was dumped by Garvey after he proposed to her, deciding to find love with another contestant Louise Pillidge.
Sam then went on to star as The Bachelorette in Australia, finding love with winner Sash Mielczarek.
When their relationship broke down, Frost and best friend Bashford found love.
Now, between filming for Home and Away, Frost shares Believe by Sam Frost as a collaborative project with her sister Kristine, aiming to "help with navigating the sometimes toxic world of social media".
Visit https://www.believebysamfrost.com/ for further information.
WATCH: Sam Frost speaks out about anxiety