I have recently cheated on my girlfriend of almost three years and need help providing perspective to a recently discovered issue I have with lying. Though I know I’ve had a problem with it for a long time, this time, I broke the heart of the best thing that’s ever happened to me. I can’t grasp it. I have moments where I lie to myself and pursue desires that I know will only give me momentary satisfaction. I’m scared and am feeling weak. 
I’d like to why I am the way I am.