Bigger Problems than what im used to

ok its me again and this time i have a worse problem
my girlfriend and are having problems again well after a hard time of argueing we got over that and now we are starting to seperate and love her so much and at times she loves me ok like we will go through a rough patch and then a good time but then its back to the fighting and she dosent open up to me like she will have a bad day and when i ask her about it and she will say she dosent want to talk about it but then she will go anywhere else and it gets better she has a son ok and i accepted him as my own ok i treated that boy like i was his father and i loved him like he was my son but im tired of all of it and i cant help but feel like she found someone else my friends say that she not good enough for me but i need a non biased opionion well thanx guys and gals
Tazz

First off, what do you guys fight about? Do you fight about the future? fight about each other? fight about not fighting?

Second, you need to tell her. have a mature talk about it..