After a while, Alfie borrows several thousand pounds from Andy to bail out Kat's father, Charlie Slater (Derek Martin), who has been arrested for assault. Andy begins demanding cash every week, which he knows Alfie cannot afford. Andy's plan to wreck the Moons' marriage starts to work and Andy offers Kat the chance to pay off the debt by spending time with him in bed. She reluctantly agrees and they sleep together, with a reluctant Kat oozing with guilt. Though unknown to her, Alfie has paid Andy the money. Andy keeps the money and gives Alfie a video tape of Kat cheating on Alfie with him. They watch the sex tape together and she reveals the whole story behind her infidelity. When Alfie insults Kat, she slaps him, with him doing the same thing. Afterwards, the couple attempt to put the incident behind them but their marriage starts to deteriorate and Alfie is unable to trust Kat. She moves out of Walford for while. During her return, it is seen that Kat has become an alcoholic and isn't bothered by the fact that Alfie wants them to resume their marriage. Kat has sex with Roger (Russell Boulter), a stranger, while intoxicated and finally sees sense, deciding to return to Alfie, but he discovers she has slept with a man she doesn't know and throws her out, so she leaves Walford again.