constancy vs two-timing

constancy

noun

  • The quality of being constant; steadiness or faithfulness in action, affections, purpose, etc. 

  • An unchanging quality or characteristic of a person or thing. 

two-timing

noun

  • The practice of being sexually or romantically unfaithful. 

adj

  • Sexually or romantically unfaithful. 

How often have the words constancy and two-timing occurred in a corpus of books? (source: Google Ngram Viewer )