On June 11th I said to Marc, "Say, do you know what tomorrow is?" Marc looks at me and says "Yeah, it's our anniversary. And you thought I forgot!" Then we had a big discussion about how neither of us wanted to spend money on gifts or flowers.
Later that day Stephanie mentioned that her anniversary was the next day. I said WHAT! and told her that both Marc and I thought it was OUR anniversary.
At least we're both approaching senility at the same rate.