Your preoccupation for high standards regarding safety around fire arms is very commendable. I applaud you for that.
Never the less, I feel sorry for you and your wife in this situation. At least in the way you describe the situation, it is obvious neither of you feel good about it.
She does not feel she deserved your treatment. She did not do anything on purpose or negligence, but from inexperience.
You are rightfully very upset in terms of being scared someone could very easily been badly hurt or worse AND that it would under such circumstances have been indirectly your fault for not judging the competence of the shooters better. You are, hence, partly being angry with yourself projecting it on to your wife as the culprit.
If she did wrong, so did you. You are in different ways both to blame. That gives you a window of opportunity in terms of being justifiably able to ask her forgiveness.
Again, I applaud you high and loud for taking safety seriously!
