Chris Albrecht, the chairman of HBO, has temporarily stepped down from his post, in the wake of his arrest in Las Vegas over the weekend. He was charged with assaulting his girlfriend in the parking lot of the Las Vegas hotel where he’d gone to watch a championship boxing match on Saturday night. Albrecht, 54, sent an email to HBO employees saying he’d been an alcoholic in recovery, but had started drinking again two years ago. Bill Nelson, the cable network’s COO, will take his place for the moment. Here’s my colleague Jacques Steinberg’s story…. Update: in a stunning turn, Albrecht resigned on Wednesday at the request of Time-Warner, ending a 20-year career at the network.