Off Broadway auds will have to wait a bit longer to see the new play by Douglas Carter Beane. The scribe’s latest, “Mr. & Mrs. Fitch,” has postponed its run at Second Stage Theater.“Fitch” helmer Scott Ellis, who also directed Beane’s comedy “The Little Dog Laughed” at Second Stage and on Broadway, recently became supervising producer/director of Showtime skein “Weeds.” The sked for that gig made him unavailable for “Mr. & Mrs. Fitch,” which was to have begun perfs in June. A replacement offering will be announced by Second Stage in the near future. No rain-check dates for “Fitch” have been confirmed.