Royal Marine boyfriend temper issues?

i am living with a royal marine, we have been together for 1 year (i have been in a couple long term relationships that ive ended but this one is different i can see a future with this guy). He gets these temper grumps though for no reason, it can be something really stupid that's really not necessary and he just clams up he wont talk to me and if i try to talk to him he gets really nasty and they can last all day, it generally upsets me and then turns into a big argument. Yesterday he went away for a week and was in one of these grumps, he didn't say goodbye just left. it was horrible, i text him and asked him to call me that evening. he did and basically broke up with me , said he hates that he gets so angry and knows i dint do anything wrong but at the time he cant see it and doesn't care if he upsets me, doesn't feel bad about it while he's grumpy and no one else makes him feel this way, but he's also never loved anyone before and hes a marine so been trained to suppress his emotions. he kept saying he loves me and wants to be with me but doesn't want to feel like he does when he gets in these angry grumps and if he wasn't with me he wouldn't get them and so it seems like the sensible answer. he says he's tried to control them but cant and hes had enough. i don't want to loose him, i really love him and i know we are good together, these grumps only happen every 2-3 weeks but hes willing to give me up because of it. what can i do?