David Foster and Katharine McPhee — 35 years
David Foster and Katharine McPhee first came into contact in 2006 when Foster was a mentor on the fifth season of American Idol and McPhee was a contestant. Although they didn’t start dating immediately, rumors of a romantic relationship between them began to surface in 2017 after Foster’s divorce from Yolanda Hadid was finalized. The couple confirmed their engagement in 2018 and got married the following year. In 2021, they became parents to their son, Rennie David.
It's not like the women are teens... Most are at least 30.