Stephanie told Buzzfeed: "They said I was topless and it was inappropriate and we're a family-oriented company."
She added: "I was a model employee, I was moving up fast. I had a promotion within seven months. This one thing, for me, was the reason I was booted."
MailOnline has contacted Austin Bank Texas N.A for comment.
The photoshoot, taken by Bria Terry of Wolf & Rose Photography, has been shared more than 85,000 times since the photographer shared the stunning lakeside images on her Facebook page.
Describing her reaction to the seeing the images for the first time, Stephanie told HuffPost: "I honestly have never felt more attractive.
"I was so nervous to see the final result. I didn't know what to expect. But when I saw the album, I was shocked."
She added: "I look so in love and confident. Every person should be able to see themselves in that light. It is really eye-opening."
Some of the sultriest images from the shoot see Stephanie and Arryn sharing a passionate
kiss while sitting by the edge of the water.
Stephanie's legs are wrapped around Arryn's waist while he rests his arms behind him, and its clear they only have eyes for each other.
The couple also took their undeniable chemistry into the lake, where they kissed and embraced while waist-deep in the water.
"A moment,
a smile;
a single burst
of laughter
that sounds exactly like
the rest
of my life." -Tyler Knott...
Posted by Wolf & Rose Photography on Wednesday, 13 September 2017
Social media users were quick to react to the images, admitting that they wished they had the confidence to do something like that.
"This makes my heart so happy and gives me hope as a plus size woman that not all men care about what size you are," Samantha Shipley wrote.
"This is so perfect," Seana Beluke added. "Their love for one another shines so bright that nothing else in the world matters, especially not the opinions of those who would try to bring them down. You did a wonderful job of capturing that connection."
Stephanie told HuffPost that she used to struggle with body-image, but over the years she has come to terms with the fact that she will always be considered a plus-size woman.
She added that she frequently pushes herself to wear clothes that that she likes but "aren't in society's mold of what is acceptable for bigger women", much like she did when she posed for the topless shoot.
The bride-to-be noted that in their nearly two-year-long relationship, her fiancé has never once made her feel self-conscious.
"He loves me for who I am, and for who I make him want to become," she said. "He has always told me that he doesn't care how I look, that I'm beautiful regardless."
Stephanie and Arryn got engaged in February, and they plan on saying "I do" in February 2019.
As for the boudoir shoot, Stephanie recommends that other couples should consider trying it out for themselves.
"It has brought us closer; made us more intimate," Stephanie told Pop Sugar. "We have never experienced a scenario of being so vulnerable in front of one another with an eyewitness.
"It made me appreciate his love for me and made me want to be more loving towards him. When I expressed this, he told me that he felt the same."
