John Mulaney, 40, posted a loving birthday tribute for his girlfriend, Olivia Munn, who turned 43-years-old on Wednesday. Birthday girl: John Mulaney, 40, posted a loving birthday tribute for his girlfriend, Olivia Munn, 43, that included a rare comment on their life as parents All natural couple: The two A-list stars are frequently spotted together outdoors with their son Malcom; …