She said: "When we first got married, we were just figuring out our life together. I felt like putting a wedding in the middle of all of that would be really hectic and stressful."
Justin, 25, was "really sick" for some time after they married, and later discovered his symptoms had been caused by Lyme disease.
Hailey says coping with the Love Yourself hitmaker during that time was challenging, especially when the public were being "mean and judgemental".
She added: "He was really sick. He has Lyme disease, and he was dealing with a bunch of medical stuff. We didn't have a diagnosis. And it was hard because everybody from the outside was being super mean and judgmental, saying he looked like he was on drugs, saying how unhealthy he looked, when, in truth, he was not healthy and we didn't know why.
"It was months of me being a new wife, trying to help him figure out what was wrong and what was going on. Now he's perfectly healthy. But going through that and then trying to be like, 'So where does our wedding fit into this?' didn't feel like the vibe at all."
And whilst it took the couple a year to overcome their struggles, they are now stronger than ever.
Speaking to the March issue of Elle magazine, Hailey explained: "He had grown up so much. I was actually shocked. I think I had grown up a lot, too. He was somebody I'd always cared about so deeply and loved very deeply.
"Obviously, it took work and getting past things between the two of us, but it was all very worth it. He's an incredible, amazing man and such a good partner to go through life with. There is no one else I would have ever wanted to spend my life with except him. So, I'm lucky."
