“I broke up with Mark because I just know long term it’s not right,” the 37-year-old said on her Let’s Be Honest podcast Oct. 1. “It’s not because of love lost or something bad happened, no one cheated, no one was mean. No one did anything. Those breakups are always the hardest, I think.”

Although she described Mark as “the best boyfriend I’ve ever had,” their 13-year age difference—which they both fiercely defended in the past—ultimately led to their breakup.

“I just know long term he needs to experience life,” she said. “He’s young, I mean, he is. I started to feel the age a little bit just with life experience. I look back on when I was 24 and how much life has happened for me between then. Those are crucial years; those are formative years. This is when you find yourself, and he needs to be able to do that.”

After debuting their relationship in February, the couple tuned out the criticism surrounding their age gap and were instead focusing on one another.

“She makes happy, I make her happy,” Mark told E! in March in a joint interview with Kaleb and Kade. “That’s what’s important, so I’m not too worried about the critics, honestly.”

Keep reading to see where it all started for Mark and Kristin.