Leanne (Jane Danson) cheated on Peter with Nick Tilsley (Ben Price) late last year, but she ultimately managed to salvage her relationship with the bookie when they realised that they couldn't live without each other.
However, as previously revealed, more trouble lies ahead for the Barlows' marriage in the coming weeks as alcoholic Peter will soon start drinking again before embarking on a secret relationship of his own with Carla Connor (Alison King).
Gascoyne told Take It Easy of the storyline: "I think he is slowly realising his feelings for Carla. I think falling off the wagon and having a drink gives him a bit of Dutch courage to express his true feelings.
"Leanne and Peter are not getting on too well because Leanne is struggling to get pregnant and has become very short-tempered. Their relationship is getting increasingly strained."
Asked whether Peter has put Leanne's infidelity behind him, the actor replied: "No, I don't think he has. He tries to, and tells Leanne that he has, but somewhere inside him it still hurts. His subsequent actions might even have a touch of revenge about them - not a lot, but it is there within him."
Coronation Street fans will see Peter drawn back to Carla later this week.
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> Coronation Street producer teases heartbreak plots
> Coronation Street star Jane Danson wants Leanne, Peter future
> Coronation Street Carla feels selfish over affair, says Alison King
> Read more Coronation Street spoilers and news
Watch a preview of tonight's Coronation Street double bill in the video below: