Please do not let anything justify this action in your head and do not let this act of aggression pass by him without any repercussions.
However you choose to handle this, this is going to be a turning point in your life.
Thereβs really only one scenario where this might happen and even then, if this happens, up until that very moment it should be very clear that the things are not working out to at least one of the partner.
My only advice – make sure he realises that his acts has impacts that affects his and others life.