As the other educator has pointed out, there are no similes in Shakespeare's Sonnet 116; there are, however, metaphors. A simile compares two things by saying Thing One is like Thing Two, while a metaphor compares two things by saying Thing One is Thing Two. Both devices enhance the meaning of Thing One through the comparison.
If you meant to ask about metaphors rather than similes, the examples in this sonnet include:
Through these metaphors, Shakespeare compares the concept of romantic love to something which cannot be moved by the storms of circumstance; it is "never shaken" by life's "tempests," but remains "ever-fixed." Like the North Star, which sailors have used for millennia to guide them in their travels, love is the soul's compass which guides lovers through their lives. Love is not "Time's fool," that is, it is not duped...
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