How to best handle

So my boyfriend of almost a year has an anger issue. Now he’s never hit me or anything like that and he never would, but anytime he get he’s the slightest bit upset he goes from 0-100 in three seconds and he gets mean and nasty. Says horrible things and just generally talks to me in a nasty tone. Whenever I stand up for myself and tell him I don’t appreciate the way he’s talking to me he gets even more upset because he says he’s not being mean or nasty. I think he really needs some anger management or therapy to learn how to better deal with his anger. What’s the best way to get him to understand that I don’t like him talking to me the way he does when he’s angry and try to bring up the therapy issue.

Now all that being said generally our relationship is amazing. We almost never fight it once in a blue moon that this happens. The reason I ask is because I can see myself marrying him some day if we can work through this and don’t want to just leave with out putting up a fight for my relationship.