Second chance? Trust?

When someone makes a mistake, they are usually forgiven and given a second chance.  But what do you do when you have forgiven someone too many times?  What do you do after the second chance is up?  Has the person worn off their second chance card because they already used it?  Is there certain things that can slide by with only a sorry? 
What if they have done something that is not reversable?  What do you do when you trusted a person that has done this to you?  What if they say sorry?  Sorry is the right thing to say right?  Do you take the apology?  Can you forgive after being hurt?  Can there be all these chances when it involves breaking trust?  I'd like to know.

- Tasha xoxox