I do not believe that a relationship ends when passion goes away since you can definitely still love someone even with a lack of passion. Like loving a person just for who they are. Like a very calm relationship. Relationships that lack passion is like those lazy relationships when both partners are quite boring people and do not really care. These people seem to just have each other and do not find passion just probably because they both have an understanding that both will not leave the other. I am only guessing that is how passionless relationships work, both partners too lazy to find anymore, they would settle. Long term couples that still have passion create new ideas in the relationship. They add more challenges or fun, they can plan new trips to take or even maybe get a dog together. (or a child) Long term passionate relationships takes work and effort and I believe it is important to at least try a little. Love probably will not end when passion fades but can maybe change. Lazy relationships with people who settle and accommodate may stay but people who need change and effort, passion fading will end the relationship. I guess it depends all on the type of person you are.