New research shows that getting acquainted with a new couple spurs passionate feelings about your own partner. "What's important is that it's a setting that allows for some deep conversation," says Richard Slatcher, an assistant professor of psychology at Wayne State University. He will present the research this week at the annual conference of the Society for Personality and Social Psychology in Austin. "Opening up about your thoughts and feelings can increase feelings of passionate love," Slatcher says. "And when you and your partner are opening up to this other couple and getting to know them, the extent to which the other couple really responds to you in a way that conveys understanding and is really validating of you increases your feelings of passionate love toward your own partner." Wayne State University researcher and doctoral student Keith Welker said: "Relationships have widely been thought to flourish and develop in a broader network of social relationships. The more that the other couple responds to your self-disclosures in a validating and caring way when on a double date, the more passionate you feel about your own relationship."

http://www.usatoday.com/story/news/nation/2014/02/10/passion-research-double-date/5289181/
http://www.telegraph.co.uk/women/sex/relationship-advice-and-romance/10630453/Forget-candlelit-dinner-this-Valentines-Day-and-put-passion-back-by-inviting-friends-around.html