Needing space when upset

How can I explain to my boyfriend that when I am upset (even when not because of him) that I need space and to be alone to decompress. I just don’t like to be touched or talked to or anything when I’m upset because I’m more irritable when I am upset and it just escalated things. I have tried over the last year to express to him that when I am upset it is better for me to be alone but because that is not how he copes with it he doesn’t understand that I need space and every time we argue and I try to get away for 5 minutes to deal with it on my own (how I need to) it just turns into a bigger argument and escalates everything. How can I help him understand that I just need some time alone to decompress anger and gather thoughts so that I can then come back and have a conversation not an argument