FI and I were having this (purely academic!) debate over the weekend, inspired by a friend whose situation -- sadly -- is not academic.
Which is worse? Emotional infidelity (i.e., your significant other falls in love with someone else but does not engage in a physical relationship out of "respect" for the prior commitment) or physical infidelity (i.e., your significant other has a sexual relationship with someone else, but no emotional entanglements)?