It was revealed in Shopaholic & Sister that before marrying Jane, Graham previously had a relationship with Marguerite from when the time she was working as a stewardess in a train station. However without warning, she called off the relationship after meeting Bill Bertram the owner of Bertram Foods and married him. He had never known about his other daughter, Jessica, until she came to visit him while Becky was away on her honeymoon with Luke.
He eventually met and married Jane. They have one daughter in Becky. However like Jess, both are very careful and close with their money, although not all the time.
When he met Jess for the first time, Graham immediately welcomed her to his family before she could even ask him for a DNA test from him.