Star Trek: Voyager - Season 3 Episode 14 -

Harry Kim finds himself in love with Marayna, a character from Neelix's Polynesian resort holodeck program. Seeking to eliminate the emotion, Harry turns to Tuvok, who interacts with the woman and finds himself falling for her as well. While Harry is overwhelmed with feelings of jealousy and betrayal, Tuvok realizes the persona is too real and discovers she is actually a lonely alien who can interact with passing ships through their computers.