Is it right to get mad about your spouse's affair if you're having an affair?

I'm a successful real estate agent in the Seattle area. I married a wonderful man who's a cardiologist and we have a 6 year old daughter together. However, I began to have an affair recently and, after some snooping, discovered my husband was having an affair, too! This left me hurt and mentally unstable. Is this right? As my mental state unravels, whoever gets in the way of my fantasies becomes expendable. Help!!!