Romantic relationships are just one type. You also have relationships with family, friends, coworkers, businesses, plus others. So the variables that influence your choice of a mate are very similar to those that lead you to a friendship, for example. The #1 rule applies to all. Given that many factors sway us at the same time, can healthy relationships be narrowed down to one rule?
Yes. Relationships can be narrowed down to the one tell-tale sign of healthiness. Relationships that provide you with loving support, encouragement, honesty, a safety net, and a genuine interest in your best self do enhance your health. The pain and stress of toxic relations harm you physically, mentally, emotionally, and spiritually. So it is crucial that the people you give a front row seat in your life deserve it. Here is the one litmus test to inform you if they do deserve your time and attention.
When you interact with this person, do his or her words match their actions? Does he or she do what they say they will?