Kym, 39, and 26-year-old personal trainer Matt got back together this year, following her split from fiancé Dan Hooper.
But the Coronation Street insists she doesn’t even think about the age gap – because Matt acts older than her.
Writing in her column for OK! magazine, Kym said: “The first time around it didn’t work as I wasn’t ready, as it was so soon after my marriage to Jamie [Lomas] ended.
“We are taking things slowly and just seeing how it goes. I know there’s a 13-year age gap but I’ve got to say, Matthew – which is what I call him – may be younger but he’s actually more mature than me, so the age gap isn’t a problem.”
Kym’s comments come after Matt took to Twitter to defend himself against claims made by his ex-girlfriend Danielle Ballard.
Pregnant Danni said Matt is refusing to take responsibility for her unborn baby – but he insisted it isn’t his child.
He write: “After ending our relationship I was then told at a later time by Danielle Ballard that she was pregnant with my child.
“I have since been told by Ms Ballard that I am not the father.
“I can categorically state that the breakdown of the relationship of myself and Danielle Ballard had nothing to do with Kym Marsh.”