THE finale of “Sex and the City” snared big numbers Sunday night on HBO – while Monday’s finale of “My Big Fat Obnoxious Fiancé” was a huge winner for Fox.

“Sex,” which ended after six seasons, averaged 10.6 million viewers for its 45-minute finale – the biggest audience in the show’s history.

Sunday’s finale was also way up from the 7.3 million viewers who watched the fifth-season finale.

The finale of the six-part “Fiancé,” meanwhile, notched nearly 21 million viewers from 9 to 10 p.m. – the season’s top-rated reality show finale. It also scored huge victory margins in all demos (adults 18-49, 18-34, etc.).

In the finale, fiancé Randi Coy and her family both snared $500,000.

Fox will repeat the last two “Fiancé” episodes tomorrow from 8 to 10 p.m. (Ch. 5).