is my boyfriend cheating again????

my man and I have been together for 4 years. he recently left for college in august ALL THE WAY IN MISSOURI. I live in california. when he first left people started telling me that he had cheated on me, so when I asked, he continuously denied it. until someone sent me proof. we took a break so I could figure things out & when he came home for winter break we talked things through & I gave him a second chance.

I know this part may seem crazy but I logged into his instagram just bc I don’t trust him ya know. and today, valentine’s day he posts thing cute pic of me & it made me all happy. until he got a dm from his group chat of “guy friends” & one of them says “go post some more pics of your ‘gf’”. why was gf in quotations? I hate seeing something that you know you’re not supposed to see & now I can’t say anything about it to him without him knowing i’m logged in his account. and whenever I bring up something about him blacking out at the bars & such he swears on everything he’s never cheated again.. idk the whole putting gf into quotations made me freak a little