this has upset me

So... me and my gf broke up last year for a few months.. didn't speak for a month but then was on and off speaking when she heard my cat died. 
It is a abusive relationship.
Last night as I was getting her to film me at dancing, this guy randomly messaged me.. saying " hey mate how are you" she then said what did this Ryan say so I opened it for her, and she read the messages from last year back in august ( when we werent togather ) they were harmless messages. Like talking about working away and shit , anyways he said I was cute and I was like hahaha u are to. That was legit all the messages said , so she crack a shitty at me and said for me to go away so I start crying and stuff cause I haven't even done anything wrong ... legit. 
Then I left dancing cause I was upset cause she wasn't talking to me and acting like I cheated or something .. over a stupid " cute" message ..
I feel like she has made me feel like I am in the wrong .. or like I'm cheating on her and now I'm to scared of my friends message me cause she always asks who it is etc..
Thoughts?