After nearly 20 years of marriage, CSI star Marg Helgenberger, 50, separates from her husband, actor Alan Rosenberg, 57. “After 19 years of marriage, Marg and Alan have decided to take some time apart. They love and respect each other and remain committed to their family.”, the actress’s rep told People on Monday.  Helgenberger and Rosenberg have an 18-year-old son.