Author Allie Rowbottom didn’t watch porn until she was 20. With roommates and a bowl of popcorn, she slid in a DVD starring blue-movie queen Nina Hartley, shrieking and throwing kernels at the TV. It wasn’t until much later that she came back to the subject, privately and in earnest. “I have preferred vintage porn in my civilian viewing habits,” Rowbottom said one afternoon in April while walking barefoot along a Malibu beach. “I just like the aesthetics better.” For all the money and mythology attached to the San Fernando Valley’s porn industry, the world has remained relatively untouched by literary fiction. Rowbottom’s new novel, “Lovers XXX,” out June 2, follows two best friends’ descent into the industry’s 1980s heyday. The author spent the last three years researching and writing the period novel, set during the VHS-porn boom and primed to join the Valley arts canon alongside Paul Thomas Anderson and Haim. On the Shelf Lovers XXX By Allie RowbottomSoho Press: 384 pages, $30 “Who’s really in power?” she often wondered in porn and other …