People who defend their stupid mangy mutts over people bother the crap out of me, so I’m probably biased here.
Dog lovers will probably be like “Omgerd you monster! How could you push an innocent little doggo! He should’ve done more than that! He was just defending his pup!” Yada yada. Well, screw em.
IMO I agree with what you did and I disagree with what he did. He needs to learn to train his damn dog to not jump on people, period. And you have the right to push it off you, especially if he’s cutting you with nails or getting you dirty.
However with that said, I don’t think you should dump him over it THIS TIME.
But I do think that you need to talk to him about this, and explain WHY he was wrong AND what he should’ve done instead. (He should have taught his dog to not jump on people in an undisciplined and wild manner, AND he should have understood why you didn’t feel comfortable with a dog jumping on him like that and scratching you. He should have backed you up.)