caught bf watching reddit prn

Me and my boyfriend have been together for 5 years and he’s my best friend, but when we got together I had a lot of trust issues and it took awhile to build firm trust with him. We’ve had numerous conversations about prn and how we both find it to be cheating. I said I would break up with him if he ever did anything like that to me. Anyways, I had a dream he was cheating on me and I checked his phone for the first time in years. I found reddit prn that dates back from 3days ago to 5yrs ago. It broke my heart and I feel like I never even knew who he was, lied to, and betrayed. I broke up with him because I can’t comprehend how I’m the most beautiful woman in the world and how he’s so in love with me, but he’s been watching this behind my back for years. Should I give him another chance, or stand on my boundaries and understand that he knew what would happen. I am just so torn and hurt.