My boyfriend gave me chlamydia, did he for sure cheat on me?

I went to the ER with pelvic pain and found out that my discomfort was caused from Chlamydia. I have only ever been with my boyfriend, so I know it came from him. I have Guillain Barre and have a low immune system as it is. I am susceptible to getting infections easily. My boyfriend is adamant that he hasn’t cheated on me. My question is could my boyfriend’s Chlamydia have been dormant from his last relationship and showed up in me because of my low immune system? Or do you think he actually cheated on me and I am just being naive? Thank you in advance for your answers.

My boyfriend gave me chlamydia, did he for sure cheat on me?
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