Should I keep my girlfriend of 8 months?

My girlfriend is very suspouis of what i do.. always askin me where i am who im with ... i haven't spent a day with her w/o her going thro my phone and check my message but she wont let me near her phone. She a great girlfriend it jus ggets annoying listenin to her askin me if i have cheated on her everyday.. But she told me she does this cause she got pregent and told her boyfirnd and he cheated on her the next day. so i dont kno wheter to keep her or not