The Collaborative International Dictionary
Concubinarian
Concubinarian \Con*cu`bi*na"ri*an\, a. & n. Concubinary.
The married and concubinarian, as well as looser
clergy.
--Milman.
Wiktionary
concubinarian
a. concubinary; living in, or relating to, a sexual relationship outside of marriage n. One who takes a concubine.