Sean has big changes ahead next week as he splits from partner Marcus Dent (Charlie Condou) when jealousy comes between them.
The couple hit the rocks when Sean reacts badly to Marcus's growing friendship with work colleague Aiden, played by Toby Sawyer.
Cotton told Soaplife: "When they've both calmed down, they have a real talk about how they're feeling. Marcus reveals he doesn't know how he feels about Sean any more and questions whether they'll be able to work through this.
"In the end, it's Sean who does the breaking up. It's utterly heartbreaking for both of them."
He added: "It's been great with Marcus and it's sad when they split up, but they do split up for the right reasons. I prefer it when Sean's single because he's optimistic. I'm looking forward to him talking about boys again."
Coronation Street airs Sean and Marcus's break-up next Friday (June 29) on ITV1.