Tina O'Brien would kick her partner out if he had a baby with another woman - unlike her "Coronation Street" character's actions.
The 35-year-old star says she "definitely wouldn't be as reasonable" as her "Corrie" alter-ego Sarah Platt, who is still with Gary Windass (Mikey North) despite him fathering a child, Zack, with Nicola Rubinstein (Nicola Thorp), insisting she is a "bit more forgiving than she should be".
Tina - who has son Beau, four, with Adam Crofts - said: "Sarah assumes that Gary's heart is in the right place and maybe she overlooks things that she shouldn't. I definitely wouldn't be as reasonable in her shoes.
"I'd be like, "Sorry? You had a baby with another person? Bye bye!"
"But she thinks they're a good team and she knows that he loves her and wants to be with her, so she's a bit more forgiving than she should be."
But Tina has hinted Sarah and Gary's relationship may not last too much longer after his latest betrayal, going behind her back and getting into debt with a loan shark, which she says has put another "hole in their relationship".
She said: "Sarah is so shocked. She had absolutely no idea what was going on. Gary very convincingly told her that the reason he had some money was that he got paid for a job in advance and I don't think she had any reason to doubt him. She believed the days of him lying to her were over.
"There's been a lot of financial pressure on them recently, but she trusted him.
"A relationship is very much built on trust and communication.
"Sarah desperately wants that from Gary and I can understand why he's keeping this from her, but I think every time he holds back it knocks another hole in their relationship really. I don't know how much more of this she can take.
"It remains to be seen whether they can get through this."
And Tina is "not sure" whether Gary and Sarah will be able to get over their issues.
She added: "It's a question of whether the relationship can survive much longer when there's such a lack of communication. She's quite a tolerant partner, but she's sick of the lies.
"In the past I would have said they could have got over this, but this time I'm not sure.
"At this point, although Sarah still loves him, she's very doubtful whether they have a future together."