Did my husband cheat or not?

My husband was a way working out of state. When he came back from the job he was acting clingy and depressed. He was also rude to everyone. We did have . Then we went to visit my mom. I tried to kiss him and have with him when we were on our vacation and he wouldn't. He said he had a weird discharge. He went to planned parenthood and got tested. Then he went away to another job. He called me later to tell me he got his results back and he had chlamydia. He said he went to a party at that job before he came back and some girl pulled his out and started to go down on him. He said he didn't want her to and he couldn't enjoy it and he felt bad and made her stop and he was afraid to tell me. Now four years later since we are still fighting about this and other cheating possibilities he tells me he had sat on a dirty toilet and his had touched the rim. He said he never cheated but since I wouldn't listen to his toilet story he made up a story with his friend about the girl going down on him and he wanted that story to be less "bad" so I would forgive him. Then he tells me he didn't have a discharge or get tested when we were on vacation. That he went away to another job and got it then. Ummmm I remember perfectly those events because they devasted me. He did get tested there and he went away and that's when he got his results. But he is making me feel crazy, but I think he just can't remember his lies and the real events. So now he wants me to believe that nothing ever happened and he never cheated and he's been trying to tell me that for years because he just caught it off the toilet at the gas station. Advice....opinions....thoughts.........