I am sorry for the specificity of my question, as I am sure few others will find it helpful. Further, I would like to thank you for your straight-forward and realistic advice, considering how highly moralized and sensationalized this information is.
5 weeks ago, I had seemingly unprotected sex (I was very drunk) with an ex-boyfriend, who was STD free as of 10 months ago, and has one sexual partner in the interim. I told my boyfriend out of guilt, and since then we have tried to repair our relation; we have had protected sex 3 times with no known condom failure and unprotected oral sex. This week, he had massive pain in one testicle, and was diagnosed with Epididemytis (ultrasound ruled out Torsion, etc.) The doctor's told him that I must have given him an STD. He has had no other symptoms besides testicular pain, I have had no symptoms and the boy that I cheated with, similarly, has had no symptoms.
They did not test my boyfriend for STDs as the treatment would be the same whether or not it was positive, but they tested me. My question is, if I have an STD, what is the likelihood that it caused the Epididymitis? I feel like it is much more likely that if I had an STD, my boyfriend did not get it from me, rather from another sexual encounter. With only 3 protected sexual encounters, I feel like it is unlikley that he has contracted anything, especially because although my sexual encounter was unprotected, it was relatively low risk (I knew the person and his sexual history). I am awaiting my results.