handsome is not a synonym for sexy.

A direct replacement is correct:

"Robert's one of the smartest men[1] I know, and I thought that he was a perfect pick for the role of moderator. When we selected Robert and he said yes, he was a sexy single man. And since that time, he’s become a sexy married man, and so I wanted his lucky new spouse to stand up. So we’ve got not only a very talented, but a happy moderator."