Definition of "monogamic"

We saw how in 'Epipsychidion' he rejected monogamic principles on the ground that true love is increased, not diminished, by division, and we can now understand why he calls this theory an "eternal law."

1913, Sydney Waterlow, Shelley‎

It embodied their spirit and carried it forward, uniting their delicate feeling for chastity and purity with the ideal of monogamic love.

1927, Havelock Ellis, Studies in the Psychology of Sex, Volume 6 (of 6)‎

And the greater part of civilized humanity living in a state of monogamic marriage, it behooves us to make the best of it, to get out of it the greatest amount of happiness that we can, obviate as much unhappiness as possible, and to do everything in our power to make it permanent.

1929, William J. Robinson, Woman‎