As a person who works in the field of high sensitivity, I just want to state that the behavior she described from her ex boyfriend is not a part of the trait. Yes, we notice more subtleties and for many sensitive people having an organized home helps to reduce overstimulation.

What she was describing went way beyond that, his need for managing his environment to perfection was actually destroying his relationship and yet he could not stop himself. This crosses into the realm of mental illness.

Being a highly sensitive person is not an unhealthy diagnosis, it is a normal temperament trait for 25% of all human beings. Her ex, who could have also been an HSP, could have benefitted from psychological support.