Should I Leave Her..?

we been on and off for 15 months i mean when im with her i don't want to be and when im not i want her back?! anyways i cheated on her early on in the relationship . she doesn't trust me and its so agitating its too much shes too insecure and clingy i guess . she always checks my facebook and has something to say about any little thing like she doesn't understand im not that stupid to do anything on facebook knowing she has one . she always wants to check my phone and gets mad and has a bitxxhh fit when i say no . nosey people just grind my gears . Last night we were at a party and i was texting my cousin she SNATCHED my phone mad as hell and said who are you talking to and just started flipping out like wtf and my friend was right there that pissed me off . then she went through it and kissed me because i really was texting my cousin and there were no texts from girls . Oh and when we left my friend threw juice at her because of how she just bugged out . What should i do with this?