Husband caught on only fans ‘27F’ ‘29M’ what should I do?

Not sure where to go with this. I’m at lost with words. Recently caught husband using only fans. I’m not upset he was on there, I’m way more upset at the fact that we’ve been trying to get out of debt and I come to find out he has spent thousands of dollars. I thought we had a best marriage/relationship (even the best sex) but I feel this has been the biggest slap in the face. As soon as I saw it, I asked him to show me the account and of course he refused to show me. Later, I was able to figure out his username and password. You best believe I tried to go through every message and transaction. I needed to know if he was having full on conversations or he was just getting off with no strings attached. I also wanted to know if he was looking at local girls I knew. He tried to justify his actions by telling me that he gets on it when he’s full of stress or anxious. It’s a way of helping him cope with everything around him. I don’t know what to believe. I feel so disrespected and betrayed. Based off the transactions I saw, some were being processed during work. Is this really a way of him coping with everything or is he a porn addict? I feel so stupid because I trusted him so much. So much then I find out he’s been doing this for 5 years. This situation makes me so uncomfortable. I don’t know if I’ll be able to trust him again. Did I do something wrong? I have always been so secure about myself. I’ve always thought I was too good for him but I believed I could change him and make him into a better man. I’m fully convinced that all men are the same. We’ve been together for 10 years, but married for 4.