Trouble getting Golden Anniversary

My favorite aspiration is Family, so I have gotten several Lifetime wants of Golden Anniversary. But I have never achieved one!!! I’ve read about how to achieve it and I thought I had all the requirements, but after the anniversary party, the Sims never recognize a golden anniversary or get platinum status. I have read where you should just keep trying. I have tried several times with some families to no avail. But I will try on all of my families, even if they don’t have it as a Lifetime want, to see if I can reach it. Maybe one of the sims has had an affair I don’t know about!!