Whitney is currently at the centre of a love triangle with Tyler Moon (Tony Discipline) and Arthur 'Fat Boy' Chubb (Ricky Norwood), which reaches a climax in the coming days as she makes a choice between them.
McGarty told We Love Telly: "I think Tyler is the one and has been all along. They have a lot of chemistry.
"Fat Boy is too much of a friend. She was attracted to him because he was safe after all she'd been through. Now she doesn't need a shoulder to cry on."
Asked whether everything will resolve itself for Whitney, the actress replied: "Yes, I hope so. I think it will be frustrating for viewers if Whitney makes another mistake.
"Hopefully she can be happy. But it won't happen yet, because she thinks Tyler's fooling around with Lucy."
EastEnders will air the love triangle drama all this week on BBC One.
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Watch Whitney's EastEnders character trail below: