Fiz embarks on a secret relationship with Tyrone (Alan Halsall) later this month as she continues to support him through his domestic violence ordeal.
Although Tyrone is still involved with his abusive fiancée Kirsty Soames (Natalie Gumede), Fiz knows that he is planning to leave her as soon as he has secured parental rights over his baby daughter Ruby.
McAlpine told Radio Times of the upcoming scenes: "Because of the unique situation that Tyrone and Fiz find themselves in, I hope that viewers will not see them as cheating on Kirsty.
"We have to remember that Tyrone doesn't want to be with Kirsty anymore and is only living this lie to gain parental rights to his daughter. Fiz and Ty have grown really close in recent months and they really are soul mates, so it is a serious relationship for them both.
"I would hope that, having been through all this turmoil, there will be a happy outcome for them both. They just need to get Kirsty out of the equation."
McAlpine added that Fiz is taking a big risk with her actions, especially as Kirsty has already targeted her once before by deliberately injuring her at Underworld.
The actress said: "Yes, I think she is playing with fire. She loves Tyrone but she's trying to be with a man who's actually not available at the moment and Fiz is under no illusion of just what Kirsty is capable of, yet she keeps coming back for more.
"I suppose if Kirsty was capable of murder, Fiz would be her number one target. But I'm not sure that she would go that far and I don't want to mention it in case it gives the writers any ideas."
Coronation Street continues on Friday (December 7) at 7.30pm and 8.30pm on ITV1. Get the Inside Soap magazine on your iPhone or iPad