TV 'Grey's Anatomy' Couple Struggles to Make Love By Robert Pace 5:00 AM PST, February 9, 2012 Balancing their careers as surgeons with their personal lives has proved to be difficult enough for Meredith and Derek on Grey's Anatomy; however, becoming parents of an adopted child has made it more difficult for the two to find alone time. 'Grey's Anatomy' Cast Has Their 'Heart on Fire'In tonight's episode, the couple struggles to find the time and place to make love on Valentine's Day. Sarah Drew From 'Grey's Anatomy' Gives BirthJust as they are about to make sparks fly in their car, Meredith's half-sister Lexie interrupts with their baby in her arms. 'Grey's Anatomy' Star Eric Dane Enters Rehab"We're never gonna have sex again. Are we?" Derek concludes.The full Valentine's Day episode of Grey's Anatomy airs tonight at 9 p.m. on ABC.