Hayler said Price was also unfaithful during their relationship.
Asked by his defence barrister Arlette Piercy why he took pictures of the messages between Price and the complainant, he replied: "Because she made out that I fancied [the complainant].
"I thought, 'this is a bit weird'."
He said he accessed her phone the same way she had accessed his, by using his fingerprint.
Asked about what this showed, he said: "The relationship is breaking down."
The court previously heard that Price messaged the teenager saying she had heard that Hayler and the girl had kissed and he had "tried it on" with her, adding later: "I will make you a little star."
Asked during her evidence about the phrase, Price said it was "a figure of speech".
On Thursday, Hayler said: "Everyone can interpret it how they want, it's very pushy. It's a very strange comment to make.
"I thought she was coaching her into [saying] something she shouldn't.
"I didn't send them anywhere, I took a picture on my phone."
He told the court he found the picture of the messages "recently" after taking his phones out of storage when moving home.
He then sent them to his solicitor.