The 60-year-old music mogul is a doting dad to five-year-old Eric - who he has with his girlfriend Lauren Silverman - but his long-time pal and former girlfriend can't see the 'X Factor: The Band' judge having any more kids because he's so ''fulfilled and satisfied'' with his little boy.
Speaking to Closer magazine, she said: ''I honestly don't know if Simon will have more children. I think he's so in love with Eric, and he's so fulfilled and satisfied, that there just isn't any love left.
''He's completely besotted with Eric. Simon was always a softie - I've always said that to people.''
The 'So Macho' singer dated Simon on-and-off for 20 years but she's admitted the jealousy she used to experience when she saw him with other women is no longer an issue.
She said: ''I used to suffer with jealousy sometimes, which is why Simon and I would always break up. But once you transition into the friend zone, there's nothing to argue about or get upset about anymore.''
The 56-year-old singer - who has adopted children Mgdalena, 14, and Zac, 13, with ex-husband Andy Willner - doesn't believe her former flame has changed over the years.
She said: ''Simon is a really, really loyal friend. I mean, we've been friends for decades and he's still exactly the same person - the same sense of humour and everything. He didn't change with fame.''
The Chats' debut album High Risk Behaviour is the most punk thing we've heard in years.
Nature-inspired songs we just can't get enough of.
Put these British films about music at the top of your watch list.
How has coronavirus affected the music world this week?
James Righton's latest album is well-produced, well-arranged and put together very proficiently and professionally.
With the passing of each decade, the music industry is constantly set alight by the...
Filmmaker Spurlock (Super Size Me) is known for his investigative wit, but there's none of...
British pop heartthrobs One Direction became a worldwide sensation when they were thrust together on...
Niall Horan, Zayn Malik, Liam Payne, Harry Styles and Louis Tomlinson may make up the...
The "Scary Movie" horror spoofs must be some kind of mutant, alien movie franchise. There's...