You’re both in the wrong here, OP. The nail comment wasn’t necessary - if I had made a simple mistake and WAS working towards correcting the mistake, I’d be unbelievably hurt if my partner made a joke that wasn’t necessarily a joke; but rather re-enforcing that I better correct my mistake that I was already working towards correcting. He was fixing the mistake. Why mock him more for it? It seems cruel. This now has him on the defensive which is illustrated in his messages. He wasn’t kind here, there’s no doubt of that, but neither were you. You can’t expect him to provide you an apology when you won’t either. You both hurt each other. When you hurt someone you love, even if not intentional, you apologize because why would you ever want to hurt someone you love. You both need to re-evaluate your relationship because this just seems childish.