As for the nuclear whistle-blower who assists her, we first saw him, decades before, in bed with the young musician. And so on, ad infinitum—or ad nauseam, if, like the publisher, you have no taste for “tricksy gimmicks.”
-- Anthony Lane, "Lost," The New Yorker, Oct. 29, 2012
And so on and so on, not ad infinitum but for a period at least--the ten years in which he managed to live and work.
-- Theodore Dreiser, Twelve Men, 1919
Ad infinitum comes directly from the Latin word of the same spelling which meant literally "to infinity."