Line forms to the left, ladies. Former NYC Mayor Bill de Blasio is back on the market after an alleged affair with an out-of-state elected official put the brakes on his 10-month relationship with progressive activist Nomiki Konst, two sources tell The Post. The couple went public with their courtship in February with de Blasio, 64, saying at the time he and Konst, 41, were “kindred souls” who had known each other for a long time. But 10 months later and the erstwhile happy couple is no more, with sources saying the former “The Young Turks” investigative reporter and Bernie...