The 34-year-old and the former rugby star lost their first child May 6, 2011 when Brook gave birth at just six months pregnant, reports femalefirst.co.uk.
Writing in an extract of her autobiography, printed in The Sun newspaper, she said: “After the miscarriage, Thom and I decided it was time to make a fresh start … Thom proposed.
“He’d bought a beautiful ring. I immediately said yes. The miscarriage actually brought us closer together.
“Later I went to see my doctor, who said, ‘The best way to get over this is to try and get pregnant again’.
“So Thom and I weren’t careful, and just before Christmas 2011, I got pregnant again. The look on Thom’s face said it all. I think he was terrified…I had another miscarriage after a few weeks.”
Brook, now engaged to David McIntosh, claims losing a second child ended her relationship with Thom, who was no longer interested in starting a family.