Want to marry fiance

The man who was living with my divorced Sim proposed to her. I did a plan wedding and went to the wedding venue I created for her first wedding. I pressed on the arch and was trying to have them get married (I planned the event and everything) and it said that the groom needed to be there. He was sitting right there. Then I tried doing the bride and it said she needed to be there and she was there too. Does anyone know what happened?