The former Beverly Hills, 90210 star met and fell in love with McDermott in 2006 on the set of their TV movie Mind Over Murder.
At the time, both were married to other people – Spelling was wed to actor Charlie Shanian, while McDermott and Mary Jo Eustace were a couple.
Spelling and McDermott subsequently divorced their spouses so they could embark on a relationship and they sealed their whirlwind romance by exchanging vows in May, 2006.
But the circumstances surrounding their own nuptials has left Spelling constantly fearing McDermott will leave her.
In her new memoir Uncharted TerriTORI, she writes, “Given our history, I often get worried that Dean is going to cheat on me. If the phone rings and it’s a girl’s voice I have to ask if he’s having an affair.
“Dean has never been anything but devoted, and he tells me over and over again that he would never do that. Deep down I believe him. But I can’t stop myself. For some reason I’m compelled to accuse him of cheating.”