With the Sunday flight from JFK, perhaps look at eastern Long Island? There are seashores, natural areas, wineries, B&Bs.....may be pleasant in late April, with placid togetherness with boyfriend before saying goodbye at JFK.

Easy logistics from Manhattan on the Long Island Railroad.....or maybe pick up rental car in Manhattan for drop at JFK? Or take train(s) to JFK to pick up a car there.....or LIRR to the station near Islip airport, for lower cost rental cars.