'Coronation Street's Steve McDonald and his wife Michelle are set to split after she finds out about his one-night stand.

Steve and Michelle McDonald (Simon Gregson and Kym Marsh)

Steve and Michelle McDonald (Simon Gregson and Kym Marsh)

Kym Marsh - who plays the barmaid - doesn't think her alter ego will be able to forgive her spouse for cheating on her with her best friend Leanne Battersby (Jane Danson) earlier this year and getting her pregnant following the drunken bunk up.

Speaking to the RadioTimes.com, she said: "I don't think so [Michelle and Steve will get through the affair]. I just don't see how she could forgive him. Who knows what will happen in the future? But certainly I think the reveal of all of this could spell the end of Michelle and Steve for the time being."

The situation recently took a turn for the worse when Steve (Simon Gregson) found out he could have muscular dystrophy - a hereditary condition marked by progressive weakening and wasting of the muscles - and there's a 50 per cent chance he may have passed the gene onto his offspring.

Michelle is riddled with worried that their unborn child could be carrying the gene and contemplates an abortion.

Kym explained: "She doesn't know what to do for the best. She's worried that she might end up having a situation where her husband is ill and they have a child who is also ill, and she really doesn't know if she could cope. It isn't something she's thinking about lightly."

But she isn't the only one petrified that her baby may have the condition as Leanne - who has battled with fertility problems for years - is also concerned for her child's health.

And the storyline, which also affects Steve's daughter Amy (Elle Mulvaney) with Tracy Barlow (Kate Ford), is set to get even more explosive over the coming months.

Kym teased: "We also know how big this storyline is going to get in the coming months, so it's exciting to be working on something which is a slow burner and has so many twists and turns in the plot. This one is just the latest one - there's more to come."