Is this worth staying?

Hi , i've been in a relationship coming 2 years, and i have suffered several trials and tribulatiions as well as minute moments of joy. Both of us have been quarreling over past mistakes we have committed. And it always comes down to the point that the girl had done greater wrongs than the guy , which becomes a questionable issue now. Girl : The girl in the past vision boys and girls both as friends that can be treated the same way despite being attached to a guy . The girl talked to many guys and SMS-ed them. So here come along this guy, called : Peter. Once, the girl left her laptop behind at the guy's house, and needed it the next day . Thus, the guy travelled down to her work area (Childcare) which took an hours journey. The girl asked him to come help out at the Childcare since he was here. However, Peter was also helping out there, and guy dislikes him in every angle. That day , after everything ended, Girl told guy that she needed to head home because her mum wanted to be home for dinner. Guy understood and said alright since girl informed him yesterday about it. So we went separate routes, and Peter 's way home was the same route as girl. While heading home, Peter received a call from the head instructing him to purchase an ice-cream cake for someone's birthday the next day . Since ice cream cakes has a tendency to melt very fast, the head told him that i was to bring it home and bring it the next day since my house was a 5 minutes walk to the place and Peter's house would be a 6 stops mrt ride. So , girl followed Peter to purchase a cake, and failed to inform guy that she was out with Peter. Guy asked girl : Where are you now ?. And girl replied : i just got home, which is 1 hours after the time i ought to be home. Guy got furious upon hearing the story, and accused girl of cheating him. // Guy: Guy had been the faithful sort since the start. However he grew up with hatred and anger in him due to his parent's divorce and lack of love. Guy hated the Girl to have many social network connections . And hence, the girl eventually devoted almost all her time to him, causing her to not return home early for dinners with her family. Guy felt that in a relationship it is reasonable to just return home early once a week for a dinner with her family, so oh well, the girl abided. Guy was very hot tempered, and always feels that what he does was reasonable. Out - talking him was never possible so the girl just got to say sorry for every mistakes she made. Guy ever abused the girl by laying hands on her , and she ended up injured. Guy couldn't stand Girl one day and went online to ordered a sex package with the girl . And well , he confessed , he had sex with an unknown girl. Most of the time, Guy cannot accept the way Girl 's actions and the way she talks. He feels that Girl is condemning her, and whenever he gets pissed , he would say :" since that guy is better, why don't you Fuck that guy ". // However our quarrel always drives down to a point that the Girl Did more Wrong then the Guy. Cause the Girl Flirted with 10 guys in the past ,and in the 1 Year changed for the guy. ( not talking to guys un-necessarily) while the Guy had done one mistake of having an unprotected sex with a Girl in the midst of our 1 year and 5 months together. ( Claiming that he had enough of it , and couldn't endure further ) . What should Girl do ?