When her symptoms became more severe in November 2017 she was told they were stress-related, he added.
After eventually being rushed to A&E in the same month, Gemma was diagnosed with adult acute myeloid leukemia and died three days later on November 24.
Simon, who is currently promoting a competition in aid of Blood Cancer UK, was left heartbroken and alone raising their son Ethan, now 12.
The pair both had therapy following the tragic death - with Ethan’s counsellor going on to make an appearance on TV.
"We both benefited from having people to talk to and we both spent two years working with our individual counsellors," Simon told The Sun.
“Ethan’s counsellor was an amazing guy called Colin. He’s an actor as well as a counsellor and we’d seen him in a McDonald’s advert, but the other week I was watching the John Darwin Canoe Man drama and he was in that.
"I showed Ethan the following morning and we both loved seeing him.
Simon has since remarried after tying the knot with lawyer Derrina Jebb last July.