I believe that the nature of a relationship with a partner has the greatest influence on the physical or mental health of an individual.
A healthy, loving relationship can do wonders for a person. In contrast, a problem there can be devastating.
As trainers, we usually are very well acquainted with those problems, and we see first hand the impact. Sometimes just an unintended bad phrase of words can upset a partner, not to speak of events like divorces or serious illnesses.