"That's left to be determined!" Abdul told PEOPLE backstage at the LG Electronics gift lounge at the Tony Awards. "I know Simon so well and honest to God, I think he's at that stage in his life where he's a grown-up Simon now, making him a great and loving husband. But he still has that little bad boy in him."
Cowell and Hussainy have been dating for nearly a year and met several years ago on Idol, where she's a makeup artist. When news broke in February that the couple were engaged, Abdul says she was shocked.
"It took me about 12 days to take my jaw off the ground and put it back up," says Abdul of hearing the news. "But Mezghan is a lovely girl and I've known her for a long time. They make a great couple and I'm happy for them."
Not that the blunt and often critical Cowell has gushed to Abdul about his fiancée yet.
"That would be an alter ego of Simon to gush about her. That is not part of his DNA," Abdul says. "However, I know that he's in a happy place so that makes me happy. He would never gush about anyone unless it was about himself and that's why we love Simon."