What can I do with my Marine boyfriend?

im so upset like rite now I jsut got finished talking to him (we’ve been together for 2 tough years)..hes in misouri finishing his marine training..a while back he told me that I was rite that he shouldnt of had left his hometown and everything for hte marines and how he regreted it..and now that I finished talking to him he sounded different like it happens everynow and then ever since he left..itslike if I dont even recognize him..he talks like a killer..he says that hes ready to go to iraq and blow stuff up and to pull the trigger on people…im like what the f*ck? it breaks my heart so bad to hear him talk like that sometimes I even think hes confused of what he really wants to do…he even asked me not to worry about him anymore..or atleast not as much..but all this is starting to come down on me..I try to tell him but I guess I never find the exact way to get to him of how ifeel and how it hurts to hear him talk like that..its weird ya know? it breaks my heart at times and makes me cry to be honest..what can I do?