How is the concept of love portrayed differently in Amoretti and Astrophil and Stella?

Edmund Spenser's Amoretti and Sir Philip Sidney's Astrophil and Stella are both sonnet collections written in the Renaissance. The main difference between the themes of the two collections stems from the authors' own experiences with love. Spenser's sonnets are written to his wife, while Sidney's are written to and about a woman to whom he was previously engaged but who married another man. Therefore, Spenser's poems celebrate the love he feels for his wife, while Sidney's poems exude much more complex emotions that fit more easily into the traditional sonnet traditions begun by Petrarch during the Italian Renaissance.
Spenser's Amoretti are dedicated to his wife, and we see in the poems his love and devotion to her. A representative poem is Sonnet 75, "One Day I Wrote Her Name Upon the Strand." In the poem, Spenser describes a scenario wherein he writes his lover's name on the beach, but the tide washes it away. His beloved says it's foolish to attempt to make immortal something that is inherently mortal; since they are human, they will inevitably die, and their love with them. Spenser begs to differ, though, asserting that he will immortalize his wife and their love through his poetry. The final section of the poem reads as follows:

"Not so," (quod I) "let baser things devise
To die in dust, but you shall live by fame:
My verse your vertues rare shall eternize,
And in the heavens write your glorious name:
Where whenas death shall all the world subdue,
Our love shall live, and later life renew." (9–14)

He tells his lover that "baser things" can fade away, but she, her beauty, and their love are not "baser things." They are higher, and they will be "eternize[d]" in his "verse." While mortal things die all around them, their love will live on through the immortal words of the poet.

Sidney's poems feature a much different tone, as his speaker is a man tortured by love. Like Petrarch in the original sonnets about Laura, Sidney feels pleasure from love and from his beloved's beauty. However, her rejection of him and/or his inability to be with her creates great pain that he also expresses in his poems. One representative poem is the sonnet addressed to sleep, Sonnet 39 in the sonnet sequence, "Come Sleep, O Sleep, thy certain knot of peace." In this poem, Sidney addresses sleep in apostrophe and personifies it as a person who can help assuage his pain. He wants sleep to come to him and to wrap him in darkness and silence, so he can have some respite from thinking about Stella. He warns sleep at the end of the poem that if sleep does not aid him,

thou shalt in me,
Livelier than elsewhere, Stella's image see. (13–14)

Not being allowed to sleep and escape Stella will result in greater pain, as his wakefulness will only exacerbate his thoughts and his pain. This is much different from the sentiment we see in Spenser's Sonnet 75. He wants his love to be remembered forever, while Sidney hopes to shut out any thought of his beloved.