The actor's character Tyrone Dobbs has been dating Kirsty for a few months, but his new relationship has been marred by the police officer's jealousy and control issues.
Earlier this month, Tyrone finally saw Kirsty's true colours when he overheard her threatening his good friend Tina McIntyre (Michelle Keegan). However, he later decided to stick with Kirsty after discovering that she is expecting his baby.
Halsall told This Morning today: "Tyrone's never had a stable family or childhood. He was only stable when he was with Jack and Vera. He just wants that family - to have a wife and a kid. And so the other things on the periphery, he just doesn't see. He doesn't see what Kirsty's doing behind his back, because he's just in love.
"Kirsty is driving a wedge between Tyrone and his friends, and just separating him from everyone so she can have him to herself and be manipulative."
Asked whether he knows any secrets from Kirsty's past which could help to explain her antics, Halsall replied: "No, but I think that's exciting for us as actors - and it will be for the audience watching as well.
"We don't know the backstory and we don't know why she is the way she is. That's really exciting - the writers have got a blank page to write on there."
Natalie Gumede, who plays the role of Kirsty, recently told Digital Spy that she is also interested in exploring the character's history.
"I've heard people say that she's psychotic, but I prefer to think that she's just troubled or perhaps slightly damaged," Gumede said earlier this month. "We're yet to find out why, but obviously there's been something in her past which has made her very jealous and have quite a few control issues. So I'm looking forward to playing that out."
Coronation Street continues tonight at 7.30pm and 8.30pm on ITV1.
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Watch a preview of tonight's Coronation Street double bill in the video below: