Saying I'm sorry proves to be the most difficult task on earth. But it is the cheapest way to save the most expensive gift (i.e relationship).
However, it becomes a lie if you continue to say "i'm sorry" but keep commiting the same mistake over and over again.
And you know, a single lie discovered is enough to create a doubt over every truth you express. So your sorry should be from your heart.
Apologising does not always mean you're wrong and the other is right. It simply means you value your relationship more.