Alfie forces her to end her romance, which Kat does, and they go away together to try and salvage their marriage. When they return, they are shocked to be sacked by Phil Mitchell (Steve McFadden). However, Kat convinces Phil to give them their jobs and home back, by telling him she is trying to repair their relationship after the affair. When her mystery lover gives her another key to their flat, she writes "Kat loves Alfie" in lipstick on a mirror. As time goes on, Alfie becomes steadily more paranoid of Kat's activity, believing she is still having the affair. Alfie follows her the bedsit where there are petals on the bed and candles are lit. She refuses to answer his questions but Alfie finds a letter address to Mr Branning. Alfie goes back to The Queen Vic where he confronts all three Branning brothers. One of their phones rings, and Alfie answers Kat's call. The phone is Max's, but Kat reveals that it is Derek she was having the affair with. Alfie kicks Kat out of their home and Kat stays with Derek, who promises to show Alfie a message on her phone where she tries to break up with him, but he plays a message where she begs to see him. Kat discovers this and an argument between them, along with Derek's other family arguments, lead to him dying from a heart attack.