Have you ever seen or known those couples that have been together for a very long time? Have you noticed how they still act like they just started dating? I bet I can guess that before they were lovers that they were best friends. I feel that this is because there is more to their relationship then just the physical or sexual attraction. These are couples that have a foundation of common interests and caring that they then build the rest of the relationship on to.
When a relationship does not have that friendship as a foundation, then when issues arise within those that are the base, then it becomes easier to end that relationship. If the relationship is based on sexual attraction, then when issues come up with sex, then the whole relationship is on the line. Same goes for physical attraction, or any type of relationship.
So my advice is, when looking for a long term relationship, maybe you should take a look around your friends one more time.
Keep it kinky,