boyfriend flirting !

Hey so last night  my boyfriend and I  We've been dating for 6 months now & I went on his Snapchat . I found out he was flirting with another female . My adrenaline was up so high I was shaking I could barely read my eyes  Must have had some dust in them (; . Anyways I texted him immediately saying ' I was going to beat his ass' he said for what and I said bc of your Snapchat . He immediately went on Snapchat & removed her as a friend .. after he FaceTimed me saying that I should give him another chance and have a date night with him this upcoming weekend .i read one text where it said that he would take his shirt I believe that's the only 'bad thing' he's done . He asked for a lot of pictures of herself & she had called him cute . When we had this talk the last time( yes it's happened twice now ) he said he'd make me feel like I have nothing to worry about . Now the following day I woke up to a couple texts from him. Whenever I see his name on my phone etc I start to shake tremendously.. 
Should I get out while I can ? Or do you ladies think people can change ?
I really appreciate for the feedback