Fidelity is a notion that, at its most abstract level, implies a truthful connection to a source or sources. (...)
In modern human relationships, the term can refer to sexual monogamy. In western culture this often means adherence to marriage vows, or of promises of exclusivity or monogamy, and an absence of adultery. However, some people do not equate fidelity in personal relationships with sexual or emotional monogamy. (For example, see polyamory and Open marriage.) Often, however, females in Shakespeare are associated with it in a negative sense, such as "She is with little fidelity". (...)
in Wikipedia
"Fidelity is a gift not a requirement."
(Lilli Palmer)
Fidelity
Being a shorty, as you see,
A bare five footer,
The why my wife is true to me
Is my six-shooter.
For every time a guy goes by
Who looks like a lover,
I polish it to catch his eye,
And spin it over.
He notes its notches as I say:
'Believe me, Brother,
If Junie ever goes astray,
They'll be another.'
A husband has to have a gun
And guts to pull it:
Few fellows think a bit of fun
Is worth a bullet.
For June would sit on any knee
If it wore pants,
Yet she is faithful unto me,
As gossip grants.
And though I know some six-foot guy
Would better suit her,
Her virtue triumphs, thanks to my
Six shooter.
Robert Service
