Violence in a relationship should never be tolerated, no matter who it comes from. However, there is a huge proportion of the population that likes to play fight or roughhouse in a relationship, which can be okay. The most important thing to remember is that both sides need to feel comfortable with it.
Also, you’ve got to make sure that it doesn’t get too out of hand. In fact, some psychologists even claim that play fighting can help strengthen a relationship, as it helps you to establish your boundaries and become more physically aware of each other. Maybe you should try it next time! With moderation, of course.