a house party with 5+ couples... would i actually walk in

ok so theres this thing happening in the home counties next month, friend of a friend hosts every quarter, says theres usually 6 or 7 couples and a few singles vetted... we've done clubs, done a private dinner once with 2 other couples, but a full on house with people doing whatever in different rooms feels like a whole different beast. my wife says she wants to try, i keep saying yes then getting cold feet a week before... anyone else been the one who chickens out at the door step? how did you push through the first time, or did you just leave and try again later... we're both 30s, been in the LS about 2 yrs now