The singer, who dated Cowell on and off during the 1980s, has recently revealed she underwent a termination after falling pregnant with the music mogul's child.
She has now opened up about the experience, insisting Cowell was by her side throughout the trauma. Sinitta also reveals she was desperate to become his wife and offer him the chance of a real family years after the abortion.
She tells Britain's The Sun, "(The termination) was a long time ago when we were both young. Simon was very concerned and by my side.
"It was upsetting and it was something very difficult that we dealt with together. It's such a heartbreaking thing to go through. It was devastating for both of us.
"I have always admitted I wanted to marry him and have children with him - not just because I love him, but because I thought I would be good for him.
"He comes from a great family, I grew up with them. I idolise the traditional family, it's what I have always wanted, had and lost.
"I think it would be good for him, that his child would thrive and it would be great for everyone. Over the years I did say maybe we should have a baby now because we're older and things are different - but he did not want one and instead we got puppies."
Cowell is now expecting his first child at the age of 53 with his latest girlfriend Lauren Silverman.