Is Demi Lovato reading “The Rules”? The “Camp Rock” star, 18, recently told People magazine the lesson she learned from her breakup with Joe Jonas was: “If I’m going to have a new romance, I’d like to keep it private. I’ll go public when I marry someone.” Prior to the May split, Lovato gushed to the press that Jonas was “incredible” and “perfect.” But “The Rules” tells actresses to talk about their mov ies, not their love lives. “Better to show up at the Oscars with an engagement ring than to talk about a man who hasn’t proposed yet,” say co-authors Ellen Fein and Sherrie Schneider.