"It was the worst day of our lives," she told the publication, adding, "For a second we both had cold feet, then 24 hours later we were both, like, 'Never mind.'"
The 23-year-old actress also opened up about wishing she hadn't experienced some of her more formative years in the public eye because it led to painful body-image issues.
"Having your adolescence being displayed in public, that's something I really wish hadn't happened," Turner said of playing Sansa Stark on Game of Thrones. "Being in the age of social media when that's happening, I think I would be a much saner person if I hadn't been documented from 13 -- your most awkward, uncomfortable, unsure-of-yourself years."
"Suddenly, everyone's metabolism slows down at 17, 18 and then that's documented," she added. "My skin and everything. People commenting on it. I was too aware of my body at a young age. And it just kind of took over my mind, it was all I would think about. Calorie counting, everything. Oh, I'll just eat nuts today."
Turner explained that finally she started going to therapy to help her cope with the pressure she was feeling about her body. She also credits her now-husband with providing her with a wakeup call early in their courtship.
"He was, like, 'I can't be with you until you love yourself, I can't see you love me more than you love yourself.' That was something, him doing that," she said. "I think he kind of saved my life, in a way."
While on Dr. Phil's Phil in the Blanks podcast in April, she reinforced how much her husband's love and support and helped her grow since that difficult chapter in her life.
"I love myself now, or more than I used to," she said. "I'm now with someone that makes me realize, you know, that I do have some redeeming qualities, I suppose, and when someone tells you they love you every day, it makes you realize why that is, and I think it makes you love yourself a bit more."
During a recent interview with ET at WonderCon, Turner discussed how leaving her GoT character behind also prompted her to seek therapy as well to help her consider her next steps.
"Six or seven months ago, just after Game of Thrones finished, I went through a bit of a wobble as I think everyone would when 10 years of your life is suddenly like gone and you will never be that character again," she shared. "I went through a bit of an identity crisis and suddenly feeling a little bit inferior. And then, you know, therapy really helped and now I kind of own everything."
The sixth and final episode of Game of Thrones season 8 airs Sunday at 9 p.m. ET/PT on HBO. See more on Turner and Jonas down below.