"I am so-so sorry it hasn't worked out … This is a very painful situation … We've had an incredible 9 months together and it hurts to walk away from," he said.
Delmege and Bowyer were both paired with different people on Married At First Sight but hooked up after filming had wrapped.
Their relationship was made public in February when photos of them engaging in a steamy makeout session in a Melbourne park went viral.
Bowyer and Delmege later revealed they felt an attraction in early episodes but waited until they had broken up to start their romance.
"I was sensing it was mutual and was like 'I'll go in for the kill.'" he told Nine, before joking that Bowyer actually "put the moves on me".
After MAFS aired, Delmege moved from his hometown of Sydney to live with Bowyer in Melbourne.
It's been a bit of a bad week for reality TV couples, with Bachelor stars Keira Maguire and Jarrod Woodgate splitting on Sunday, while Megan Marx and Jake Ellis announced their break up on Tuesday.