The poem
Th' expense of spirit in a waste of shame Is lust in action; and, till action, lust Is perjured, murderous, bloody full of blame, Savage, extreme, rude, cruel, not to trust, Enjoyed no sooner but despisèd straight, Past reason hunted, and no sooner had Past reason hated as a swallowed bait On purpose laid to make the taker mad. Mad in pursuit, and in possession so; Had, having, and in quest to have, extreme; A bliss in proof, and proved, a very woe, Before a joy proposed; behind, a dream. All this the world well knows, yet none knows well To shun the heaven that leads men to this hell.
There is no "I" in this poem, which is quite unusual for WS, but in many ways (linguistic and otherwise) this poem is saturated with it's author.