Today, in the subway station in Rockefeller Center, I reached into my coat pocket and pulled out two objects: my New York MetroCard, and a ticket for the Paris Métro. For an instant, I was unsure which one to use. As I tried to orient myself, hoards of commuters whipping past, it dawned on me: this is my life now. Paris on Sunday; New York on Monday.

Before I bought a place in Paris, I would visit biannually in spring and fall. These trips punctuated my year. I’d plan for weeks—shop for new outfits, start packing way ahead. When I’d arrive, a transformation would take place. Dollars would get swapped for euros in my wallet, a rental phone would be activated, and—flick!—my Paris self switched on. But now that I’m returning about every six weeks, it seems the switch is always on. Euro coins jangle together with their US cousins in the bottom of my purse, and yes, occasionally I forget which metro system I’m riding.

The biggest shift is that Paris no longer feels foreign; I no longer need time to adjust to it when I arrive. Part of me is always in both places now, like a time traveler carrying on two lives simultaneously, two alternate realities, two possibilities—continually connected by Facebook, to-do lists, party plans, projects. I float between my two cities seamlessly, effortlessly. Like getting on the train at 14th Street and exiting at Rue des Boulets.