According to the Sunday Mirror, the new storyline will see Ian, played by Adam Woodyatt, cheat on wife Jane after overhearing her admitting that she doesn't love him any more.
Glenda will apparently woo him while he drowns his sorrows. When Jane discovers his infidelity, she becomes even closer to friend Masood Ahmed.
A source told the paper: "As ever, Ian will end up at rock-bottom."
At 55, grandmother Glenda, played by actress Glynis Barber, is 14 years older than Ian.