Many years ago- about 15- I had a reunion with an ex. Saw him a few times and we ended up being physical but not full sex- oral sex.
Would you regard this as adultery/infidelity- or like Bill Clinton thinks, is penetrative sex the only definition ( it is in law anyway.)
For me, I stopped short of the final act an drew a line in the sand, but am I kidding myself ?I am still with my DH after 22 years.