how important is the spark?

So I've been in a good solid relationship for a while now. I care deeply for him and my freinds like him. However in a relationship can the spark that exists between two people when they first meet fade?? I think we all know that the answer to this is yes it can. But what can we do to desperatly keep the spark. We can claw onto to relationships but do we actually attempt to fix them.

As human beings are we too scared to actually examine ourselves and our faults. Do we too easily blame the other person that they've changed and that what first attracted us to them is now gone. We all remember the stomach rolls that comes with his first touch and his first smile. But what happens when you are so used to this touch that you no longer feel special everytime he looks at you?

How do we get the spark back and keep it firmly in place????