Complex sentence: Sajak and White have hosted the nighttime version continuously since it began, except for two weeks in January 1991 when Tricia Gist, then the girlfriend of Griffin's son Tony, filled in for the honeymooning White.
Split into simpler sentences: Sajak and White have hosted the nighttime version continuously since it began, except for very limited occasions. During two weeks in January 1991, Tricia Gist, then the girlfriend of Griffin's son Tony, filled in for the honeymooning White.