Believe it or not, what you did was DBing. Ideally, these discussions would be peaceful indeed. However, if he chooses to be angry, you have to either endure that, or cut off communication until he calms down. You may want to consider stopping immediately any conversation that you do not deem civilized. That means at some point you say "This conversation is over" and you do not say anything at all from there on.
After that, every subsequent conversation should start with "Are you sure you can talk about this without swearing and shouting?", "Are you absolutely sure you can talk about this without swearing and shouting?", and "I do not think you can talk about this without swearing and shouting?"
Remember, you are enabling his bad behavior for as long as you participate in a conversation when he curses.
You have not made 100 steps back. You are moving forward.
