You should invite your friends' significant other to group activities.
Walter is planning a party, and has found out his old friend Harold, whom he hasn't seen in years, is now married to Maude, a woman he didn't like.
Walter wants to invite Harold to his party.
Walter invites both Harold and his wife Maude to the party.
Walter invites only Harold, and does not invite Maude to the party.
Harold and Maude gladly accept, and all three have a good time.
Maude feels slighted, and Harold has to turn down the invitation.