Need help.GIRLS PROBLEM?

let me start by sayin im very aragant and i preety much think i can snatch anyone i want>but anywho i have a girlfriend i really like her but i been cheating on her since the first day wit my ex-girlfriend that im still in love wit and can let go. on top of that i stay flirtin wit other people specialy dis girl sarah we are friend but now we startin to have feelings for each other altough she been knew about both my girlfriend and ex she's gettin really jealous and im gettin scared she will do anythin to get me even ruin my relationship wit my girl.