Every person who’s married technically has a prenup — either written by the government in the form of a marriage license, or by the two people who chose each other out of the other 8 billion people in the world. And one expert believes a conversation about having a prenup could and should take place — shockingly — as early as the third date. James Sexton, a prominent New York City divorce lawyer, recently went viral with that suggestion , fueling the long, heated debate over the so-called “prenup myth” and the negative connotation of the difficult-to-bring-up contractual arrangement. Divorce attorney James Sexton — above right, with “Modern Wisdom” podcast host Chris Williamson — believes a prenup conversation should happen as early as possible in the dating game. Modern Wisdom/YouTube In fact, Sexton told The Post that making an early conversation the norm is simply a viable way to gauge how a potential long-term partner thinks about money, risk and commitment.…