Is he cheating? so suspicious,i need answers, please? :/ 10 pts. best answer.?

so, i've been seeing this guy for about three months...i know with seeing someone, your not just obligated to one person, but he controls me that way, so i think he should just stick with me too....well, this guy is super nice, next to amazing if nto already so, he's always put me first and he's just been a great, great guy. however, lately, things seem a little weird all of a sudden. since last monday, he's been telling me he can't talk and then he'll shut his phone off at night, he's been starting fights with me and being really mean, he's been hanging w/ his friends more, going places that he's never usually gone to, and he's been accusing me of cheating WHEN I'M FAR FROM THAT...i've never cheated so he should know im not! he says he doesn't know when he will see me next, etc. and i'm just lost..i'm so lost, i'm dying inside, i love this guy, i fell in love, he said he did the same, and out of no where; in the past week he's been this way....i know his friend has a new girlfriend and im scared she's bringing a friend for my guy...but idk! am i paranoid? i've already tried talking to him, he gets defensive and tells me to stop and then turns it on me out of no where! im sooo sad, how do i cope? how do i deal? i need answers....do i let this guy go? or do i hang on? :/ please......