Should I break up with my girlfriend?

[Eric]

I've been dating my girlfriend for about 9 months now and in those 9 months things have happened that I cannot get over.

We've broke up 5 times now and every time I decided to take her back because I really do love this girl.

The first time we broke up she called me and said she wasn't happy in our relationship, so we went separate ways. She called me a few days later wanting to get back with me, so I do.

The second time we broke up, I broke up with her because she went to a party with another guy and didn't tell me. She had sex with him almost right after the break up and they were both drunk.

I was devastated because we lost our virginities to each-other. We get back together and she breaks up with me a few days after. Again, we get back together and settle everything. We break up a few months after because I smoked pot. We were broken up for 3 weeks and she had sex with a guy she met on instagram. (social media) she said she's learned from her mistakes, any ideas?