A successful relationship I think, depends on the affinity. Affinity is if they like about the same things. If they do not, one has to sacrifice. But if they like the same things, (70%) or recreational activities and routines, they will be happy. Example, routine, open windows, a person likes to fresh air coming from outside, the other closes windows, thinks the person wants more privacy. Or temperature, one turns on the AC the other is freezing. Or the beach, one loves to take sun, the other hates sand and wants to be a inside. Or going to the movies, one hates romance the other hates action. Etc. Cant live together. Will be like cats and mouses. Because a person can be considerate until certain point, after a certain point they get tired and realize that they are not compatible.