End of understanding

Each time you hurt me you say you're sorry I try to understand and say okay
But there must be an end to understanding and the end of mine can't be too far away
I try to understand you're only human and we all make mistakes every day
But there must be an end to understanding and I know that I just can't go on this way
Don't you know that love and understanding go together
Ask too much of one and both will die
And there must be an end to understanding
And I know someday I'll reach the end of mine
And I know someday I'll reach the end of mine