Hehe,
Seriously guys,the key is to always make sure that the reltionship is not 'the be all and end all' of your life. Sure, a relationship should be built on trust and love, but what most people do is sacrifice their self respect, independence and dignity for that...and that, ironically, is what causes relationships to fail in the long run.
Many reltionships consist of people with the mindset of do everything together, make every decision based on the effects to both partners. Sure, sometimes that is needed. But you need to keep some independence and do things for yourself and your own individual benefit. From my friends and the ones in stable, long term relationships, this is exactly what is happening.
And if and when your relationship does break up, remember...you still have yourself. And now, it's party time