"It's hard, it was a big decision. We have been together for seven years which is a long time, so it's very upsetting," he told the publication. "It's really hard to even talk about it. When you're with someone that long, especially in the public eye and she's someone private."
"We had some struggles and we tried to push through them as best we could, but it didn't really work out the way we thought it would," he continued. "I still love and care for Colleen but we've both determined that it's the natural end."
The former TLC star revealed problems in the relationship began to appear last summer, adding that he and Conrad broke up more than once and went to couple's therapy to try to work through their issues.
However, things took a turn for the worse at the end of 2020 when Gosselin contracted Covid-19 and was hospitalized for 11 days and missed 47 days of work as a result. Although Gosselin said Conrad was "super supportive," his battle with the respiratory illness only put more strain on their relationship.
The "Jon and Kate Plus 8" alum -- who shares 17-year-old sextuplets, Alexis, Aaden, Joel, Leah, Hannah and Collin as well as 20-year-old twins daughters, Cara and Madelyn, with ex-wife Kate Gosselin -- said he and Conrad "decided to terminate" their relationship in February. Gosselin added that he "made plans" to relocate from Pennsylvania to Florida, but decided to stick around as his kids who live with him -- Hannah and Collin -- wanted to stay in school.
However, then in April, Conrad was diagnosed with breast cancer, with Gosselin describing the diagnosis as a "huge shock," "heart-breaking" and "scary."
"I love Colleen so I decided to stand by her and do the best I can, I cared for her regardless of the state of our relationship," he said. "I wanted to see it through and support her through her treatment and work through it all."
The part-time DJ said he "tried to support [Conrad] as best I could," sharing that he went to "most" of her doctor appointments and even did research. "I think I did my best for her, trying to be the best kind of friend, I guess, while knowing full well that we might not end up together in the end," Gosselin explained.
He went on to clarify that their breakup was "mutual" and was "something that was being discussed before Colleen's diagnosis," stressing that it had "nothing to do with cancer."
"It's always very difficult to end a relationship, but I think we've given it a pretty good go," he added of the split. "We tried to blend our family as best as we could but it just wasn't working out. It's hard because I love her and care for her and I want the best for her, but I also want the best for myself. Now Colleen's health is in a better place, I have to start looking out for me and my family and my kids. I'm thrilled to move on to the next chapter in my life."
Gosselin and Conrad began dating in 2014.
Meanwhile, Gosselin sharing the news of the breakup came just a few days after Conrad revealed she was diagnosed with breast cancer back in April. Conrad posted about her diagnosis on Instagram last Sunday.
"I have been putting this off and debated even posting…I went for a mammogram on 4/15. I had put it off for almost 2 1/2 yrs due to lack of time and Covid and later got a call that a mass was found in my right breast," she captioned the post, below. "Everything after that happened so fast. Then on 4/21, I got the call that is confirmed it was cancer. Stage 2, breast cancer. I was BRCA1 and 2 negative. Everything seemed so surreal."
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"I had a single mastectomy done on my right breast on 7/14/21 followed by a DIEP Flap procedure on 7/30/21 and I feel good," she added. "The DIEP flap was a personal choice for me. I am very happy with the outcome but I also had amazing surgeons at Penn Medicine in Philadelphia. After my surgery I found it had not spread to the nodes, thank God, and they were able to downgrade to stage 1. I'm still waiting on the Oncotype number to see if I need chemo. If less than 25 I won't."
Conrad also stressed the importance of getting mammograms and doing monthly breast exams.
During his interview with The Sun, Gosselin said he and Conrad are "still living together, but [they're] not communicating very effectively or at all right now."
"We're just trying to get by, it's just very fraught," he said, before sharing that he told Conrad that he "found a new place to live."