monogamy myth?

[cocoface]

Someone once mentioned a poem called the monogamy myth I think - can anyone point me in the right direction? - I can't find it via Google. Thanks

I never was attached to that great sect

Whose doctrine is that each one should select
Out of the crowd a mistress or a friend,
And all the rest, though fair and wise, commend
To cold oblivion; though it is in the code
Of modern morals, and the beaten road

Which those poor slaves with weary footsteps tread
Who travel to their home among the dead
By the broad highway of the world, and so
With one chained friend, perhaps a jealous foe,
The dreariest and the longest journey go.

Shelley, Epipsychidium (part of) - prob not what you had in mind, but quite a good fit.

It's lovely would still love to know where to find the other one though - anyone?