In politics, an extra-marital affair can jeopardize a career. But in music, cheating is the subject of some of the most popular songs ever, from Marvin Gaye’s “I Heard It Through The Grapevine” to the Eagles’ “Lyin’ Eyes” to TLC’s “Creep.” (Don’t get us started on operas. OK, do.) We look at some of the best, with Washington Post classical music critic Anne Midgette and WNYC cultural reporter Siddhartha Mitter. Plus, we take your calls (anonymously, if you wish).