bedlock

noun

1. (uncountable)A relationship where an unmarried couple shares a bed; cohabitation.

   “He wants you an' me to fall dead in love, an' be j'ined in bedlock.”

   “Not a single pleasure is risk-free; Who in his own wife's lap now lays a confident head? Neither in wedlock now nor in bedlock can we be.”

   “If Rose is having a tennis party it may make more sense to include Joe's steady tennis partner, Sue (with whom he has never had sex), than either his wife (from whom he has been separated for four months) or Dizzy (a current partner in bedlock whose most outstanding qualities are neither athletic nor intellectual).”