The struggle is real

Well where do I start.... I'm a Male in my late 30's. Like most I started looking at porn images in my teens. Soft core images gradually progress to hardcore porn. Which involved masturbating. Here lies my biggest problem the combination of the 2 has ruined any kind of "normal" sex life for me. When having sex I have no problem getting an erection but sadly will lose it 2 to 5 mins into sex. Doesn't matter if it oral or vaginal sex. You can only imagine how stressful this for me and my girlfriend. Of course she thinks the reason is that im not into her and that she cant satisfy me sexually. I haven't had the heart to tell her about my addiction. I just make an excuse or try and change the subject. I tried so many times to break the cycle. The longest was 6 weeks without masturbating or watching porn. But like a true drug. I need that release and fall right back into the trap. Which then cause to binge because now I feel bad and guilty. I'm just really at a lost, this has affected my whole being.