Oh hell to the no . if someone hit my child there would be hell to pay . This seems as though it went beyond a simple spank on the butt , which in my opinion is still inappropriate , but if she left marks on him that ' s abuse . You have every right to be upset and I think you were right in removing him from the situation . That being said I maybe would have told your wife of your plan to leave rather than leaving and texting . I would have a serious conversation with your wife about what you will and won ' t tolerate from her family and make it clear that unless she can communicate those boundaries to her family you don ' t feel comfortable with your child being around them . I ' m all for teaching kids not to be shitheads , but this woman slapping your child over an accident . something all kids , do is beyond inappropriate !