John Mayer hinted at why he and Katy Perry broke up for the second time on "Ellen" Tuesday.

Mayer is known for talking about his past loves, such as Jennifer Aniston, Jessica Simpson and Taylor Swift, and their sex lives. Yet, he was more private about his relationship with Perry, telling comedian Ellen DeGeneres, “It was a very private relationship going in, it was a private relationship during, and it’s a very private relationship still.

"I can understand asking the question based on some previous answers I’ve given, but I finally learned how to put the wall between one thing and another,” he continued. “Coupling is a tricky thing.”

According to reports from Us Weekly, the couple split at the end of last month for the second time, after Perry, 28, began dating Mayer, 35, during the summer of 2012.

"It's sad," one insider said. "It's not over until it's over. You have to see how things play out."

Perry was previously married to British comedian Russell Brand. They finalized their divorce in 2012.

Reports claimed their relationship was over by the end of the summer, but in October the two were photographed together. Perry even brought Mayer home to her Christian minister parents for the holidays, leading people to think the couple was quite serious.

It remains to be seen if they will give their relationship a third chance.