They have found love is actually just a chemical in the brain that you can create by provoking certain scenario. People tend to use this a lot for building relationship not knowing that this, has a chemical, come and goes...
Being not steady, and the sole foundation of their relationship, the relationship fail in the long run.
Instead of seeking instant gratifications on current emotions, some people have learn to not allow their emotions control their decisions in life and be with friends instead. Where they can fall back on friendship between the time they create "Love session chemical" from time to time.
Sadly, this technique take a lot longer to implement and wasn't accepted by people in a hurry to get laid.