The reality star met model Hannah on the last series of Love Island and, after a whirlwind romance, he proposed on TV and she accepted.
But their fairytale didn't last and, once back in the real world, they later split.
Jon, who joined TOWIE this series, spoke about Hannah on last night's episode. Although he didn't mention her by name, it was clear who he was discussing while he spoke to Chloe Sims at a record store.
"It was a proper messy relationship," said Jon. "I got engaged, like. I have never done that before! But I couldn't carry on in that relationship. I was so unhappy. I got to a place where I weren't myself."
Jon said that "because I'm a boy" he couldn't really talk to his guy friends, meaning he felt pretty alone. "I've dealt with it now, it's cool, but I had to deal with it myself and I was probably the most grown up I've ever been.
"It was just difficult really. I dealt with it all on my own. You can't really go to the boys, aw, listen, bro, help me out. They would be like, shut up Jon, let's go out and get some birds. I just need to start getting back to my old self again."
Hannah told Reveal after the split that she was "gutted" by how things turned out, and admitted she'd started to wonder whether it had been real at all.
"I'm gutted because I'm now thinking it was all an act on his behalf," she told us. "Just one day after we split he was out at clubs with different girls and showing off about it on Snapchat. I don't know if it's because since we've come out the show all the attention has gone to his head. The hard thing for me is because everyone watched the show and saw him being lovely and him treating me like a princess - no one has seen his true colours."
Jon said: "I'm gutted that we broke up and I'm still gutted about the whole situation, but she seems to be moving on now. She's happy and I'm trying to make myself happy as well."
TOWIE continues Wednesday at 10pm on Wednesday
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