I am the girlfriend of a porn addict

We started dating years ago and are very close. He's a great guy with a good heart but I started noticing some signs early on with him and his commitment. He was surrounded by bad influences but he seemed to be strong enough to abstain from most of them. He would occasionally tell me he watched porn in the beginning of our relationship and I was upset about it because we had a really good sex life. He even told me that after his last relationship he would binge watch porn. He would have weird feelings that he's gay and he would need to do it. That sometimes it was uncontrollable and "just a bad habit that he did when he was bored". I did all that was in my power to "satisfy" him and he definitely satisfied me. Around 9 months into our relationship he joined an app to chat with women and started sending nudes. It wasn't the last time that happened. The first time he felt honestly bad and told me what he had done. But as time went on he would do it for months, or a few weeks at a time, and I would find out if I ever saw his phone or did some serious snooping. It has gotten to a point where I feel really insecure about myself. Because I know I will never be able to compete with the way these women are. I am generally a calm patient person but this really puts me one edge. Its making me aggressive that something out of my control is happening to me and I don't know how to not let it happen anymore. I know I am a good girlfriend because we have had no other issues other than this. It hurts to find things out through his phone or email and it has really shaken me up. I don't know how to trust him. I don't know how to feel about myself I don't know what I can change for this to not happen anymore. This has really forced me to be stronger. But I am weak. It got to a point where I just wanted to kill myself because I put in so much effort into this relationship. Being in long distance, I really tried to visit as much as possible, offered phone sex, nudes etc. It was three weeks ago I found out he had gotten another such account to chat with women. He swore to never do it again and he even found this page for support. He started participating in other activities and went strong for these last few weeks( at least I believe so). He signed up for nofap. Yet, just today, here we are again. He relapsed and watched porn. What am I supposed to do now.