Triploidy pregnancy resulting in m/c... questions!!?

I had a miscarriage at 12 weeks due to the baby having a whole extra set of chromosomes 69,XXY. He was a boy :'( I was told it could have been caused by either 2 sperm fertilizing one egg or the egg had an extra set of chromosomes. Either way it was an egg malfunction. What are the odds of my eggs being dysfunctional? It's supposed to be practically impossible for 2 sperm to fertilize one egg, but it happened to me? Could my eggs have a problem with releasing the chemical that stops more than one sperm from fertilizing?? My husband and I are going to start trying again after my next period but I'm sooo nervous this will happen again!