My girlfriend past is hurting our relationship =[?

Ok guys well i love this girl and she loves me too...how i know? because every time we fight she would always explain and how we shouldn't be fighting over something stupid..95% of the problems was her past because when it bugged me n we usually end up fighting about her past..Ive broke up wit her about one of her past and then she cried her heart out..didn't feel like talking went to sleep woke up wit 45missed calls all from her=[...so finally i sat down n she explain everything n we got bak together..i love her n she loves me...i want to be happy wit her 24/7 I DO!! but sometimes its js her past tat bugged me wat should i do guys?? she said this when i bring up her past "Whatever happen in the past..stay in the past...what count is now the present and i knw i will have the future with you" GUYS HELP PLEASE =[ i can't let go of her past =[