Germaphobes vary.
I feel uncomfortable when people cough, sneeze, etc and cover my face or wear a mask. Never touching my face, trimming my nails, and cleaning doorknobs, light switches, etc provide peace of mind. Hand sanitizer in my purse after touching store card pads, door handles, and escalator rails. I also run an air purifier in my home and it has additionally helped during allergy season. Sometimes just using any form of fragrance is enough to calm me down from worrying about filth. The covid pandemic has been pretty validating as my efforts have proven their value. What scares me is not coming into contact with germs, it's not being able to clean myself afterward.
To answer your question, sex doesnt gross me out but oral sex does. I dont like the idea of kissing after oral. I also dont like anal sex for obvious reasons. Regular sex is fine because it's an inherently clean process. The human vagina is very good at cleaning itself and all other surfaces involved can also be cleaned.