Walking away when someone is yelling at you is a perfectly fine boundary.
Thanks PH, I should've been more clear. I know walking away or ending the conversation is a good boundary but I never know what to say or if I should say anything. Often I just end up with "ok, well I've got to go, bye". I get nervous when I'm getting yelled at and my auto mode is to just get out as quickly as possible, so I end up ending the conversation without explanation really. If I try and defuse it by saying "ok, I don't like being yelled at/why are you yelling just talk to me" then he only gets more upset.
Me: 24 H: 26 2 SS: 7 & 5; D: 3 H filed D papers: 8/2/10 OW discovered: 08/10 D papers counter-filed: 10/2/10 There is no method to my madness
"When you start yelling me when we're talking, it makes me feel like you don't care what I think. I want to understand what you're saying and feeling, and to do so, you need to speak to me without yelling. Otherwise I won't listen to what you say."
Then the next time he starts to yell, just walk. You need to keep enforcing the boundary until he learns to act like a grown up.