Slater has claimed Price sent Grealish and Walker messages after a night out which involved alcohol.
He told The Sun: "We were out at a karaoke bar and having drinks, having fun.
"The bar closed, so we went home and Kate wanted to carry on drinking or playing drinking games with her friends. I was tired, so I said, ‘I’m gonna go to sleep’.
"Kate went upstairs with her friends. I woke up at like 5-6 am and she wasn’t there.
"I walked upstairs to find where she was and then, on the phone, she was messaging the footballers. It was Jack Grealish and Kyle Walker.
"Obviously there was a lot of drink involved, so I was able to kind of give the benefit of the doubt and see past that. But in the back of your mind, you’re kind of thinking, ‘I wouldn’t do that’."