person A: I can't believe I was so stupid to believe this...
person B: What happened?
person A: My boyfriend.  I knew he cheated on me but he said he wouldn't do it again. 
person B: Well_comma_ you gave him the benefit of the doubt. It was his decision to cheat. 
person A: True. Makes me feel so dumb though!
person B: Now you have more information to base your next decision on. You live you learn.
person A: Agreed!