monoamorous

Etymology
Attested since 1992, from (which see), possibly modelled on.

Adjective

 * 1) Being exclusively faithful to one partner;.
 * 2) * 1992 June 10, Jamais A. Cascio=, Bi/Polyamory Blend,, Usenet:
 * That is, if we were monogamous/monoamorous, she would not have had a chance to explore these feelings without threatening the relationship. Our first few threesomes were very much oriented towards Janice, with less attention given to me (which turns out to be okay; as the saying goes, "I like to watch")[.]