disbelief vs infidelity

disbelief

noun
  • The loss or abandonment of a belief; cessation of belief. 

  • Astonishment. 

  • Unpreparedness, unwillingness, or inability to believe that something is the case. 

infidelity

noun
  • Lack of religious belief. 

  • Unfaithfulness in some other moral obligation. 

  • Unfaithfulness in a marriage or an intimate relationship: practice or instance of having a sexual or romantic affair with someone other than one's spouse, without the consent of the spouse. 

How often have the words disbelief and infidelity occurred in a corpus of books? (source: Google Ngram Viewer )