I don't know. Did you make it physical first? Did you hit him or kick him or push him or something? Was he defending himself?

There may be a middle ground, like putting off the wedding and insisting he gets help first. You can't wait decades for him to grow up on his own and learn that he has better options. What he needs is more options. It sounds like he made it physical first. That shouldn't be on his top ten list of responses.