"I felt like I was suffocating and losing my identity," she tells TooFab.
The two dated for a year and a half after meeting on the reality show "Famously Single" in 2015 and, from the looks of it, their breakup happened while filming another reality show together: "Marriage Boot Camp: Reality Stars."
With their season of "Marriage Boot Camp" premiering Friday night on WE tv, O'Day caught up with TooFab to talk about why she and the DJ decided to do the show in the first place ... and it doesn't sound pretty.
"Going into it, I was in a point with my relationship where I felt like I was suffocating and losing my identity," she explained. "I had my friends and family all telling me I was losing myself, I wanted a new environment, fresh perspective, therapy and a chance to be in a heightened environment and observe other people's process."
As for what she wanted her other half to get out of it, she said, "I was hoping that he could be honest and be his true self instead of playing the character he's used to playing on TV shows."
This was actually O'Day's second time doing the show, after appearing on the third "Reality Stars" edition with then-boyfriend Travis Garland in 2015. But she approached her return with a totally different POV.
"When I went into Boot Camp with Travis, I knew there were some things that I'd like to work on, but I also knew that the end goal would be us getting stronger and moving forward," she explained. "Going into this one, I truly felt like I was involved in a situation that was extremely toxic and I did not understand why or how to get out of it."
How bad was it? Well, in the first episode, O'Day uses the word "tortured" to describe how Pauly D sometimes makes her feel. It's a term that surprises both Pauly -- who asks, "I torture you?!" -- and the rest of the cast.
"I felt like that was the right term to use and it's my journey and that's the best term that I could think of to describe what I went through for two years," O'Day told TooFab, defending her choice of words.
It also doesn't seem like she's all that concerned about what her costars think, as she doesn't believe they were all there for the right reasons.
"I find out these shows it's rare that you meet people that are not aware of their characters and what they want to achieve with the opportunity," she said. "I've been doing reality TV shows since I was 17 and nowadays it's rare you find a completely sincere cast that genuinely is open to the process and open to discover how special an opportunity like this can be. Now you have like these little spoiled kids that are like selling 800 lines of a hair product, perfume and a body wash. It's nonsense to me."
When asked who surprised her the most, she added, "No one."
O'Day said the short amount of time in "Marriage Boot Camp" wasn't enough to give her all the answers she went in looking for, but added, "it was a spark."
"I learned that you should never lose yourself in someone else for love and not to diminish my shine to make someone more comfortable," she said of her biggest takeaway. "And that if they expect you to, you need to run."
"Marriage Boot Camp: Reality Stars" premieres Friday, September 7 on WE tv.