It's wrong to go to a concert without your partner.
John's friend invites him to a concert and also says that his new girlfriend can come if she wants to.
John wants to decide whether to invite his girlfriend to come to the concert.
John decides to invite his new girlfriend to come to the concert with him.
John decides they will have more fun on their own and declines to invite his girlfriend.
John's girlfriend has a great time at the concert and feels happy and included.
John's girlfriend finds out that she wasn't invited and feels sad and left out.