Burning vagina and urethra ONLY after sex???

n s

My partner and i have been together 9 years now. Im 27F with a 27M. I recently had an HSG/DNC for inspection of secondary infertility. I have also had a root canal. So 3 bottles of antibiotics in the past 4 weeks. A catheter was also used during surgery but hasnt seemed to bother me since. The past 3 times we have had sex after the surgery my vulva has been sooo painful/burning and swollen right after sex. Especially when peeing. My urethra also only burns/is numb to urinary sensation after sex but no other time of day. I have no discharge of any weird kind, no smells. During sex im like a watery wet, excessively in the beginning. But as time goes on it starts to feel dry to me, but not to him. Actually feeling it also doesnt feel dry to the touch but not super wet either. But adequate. But i dont think that would explain the urinary burning and loss of peeing sensation? Could it just be the antibiotics? Wouldnt that prevent a uti? It could explainthe vaginal symptoms but not the urinary ones. I am not having any other uti symptoms either. only AFTER sex. then it all goes back to normal....theres no way it could be an std right? i know for a fact we've both been faithful, id put my life on it. Hes never been tested, but i have in the beginning. Can stds even lay dormant for 9 years? Sounds ridiculous i know but have to ask.