With regard to Shakespeare' view on life, love and human relationships, I would say that all are intertwined. Love is the most important thing in life, life is about loving someone, and human relationships center around love and life—and the relationships of most people are similar in some way: there is a commonality. Shakespeare's sonnets are timeless in that even hundreds of years after his death, his words still resonate with readers today.
In Sonnet 116, Shakespeare notes that love is a constant in life that does not change when faced with change or hardship; it remains steadfast:
...Love is not love
Which alters when it alteration finds,
Or bends with the remover to remove:
O, no! it is an ever-fixed mark,
That looks on tempests and is never shaken...
In Sonnet 130, Shakespeare refers to love and to human relationships. The speaker describes his love for a woman who is not beautiful by the traditional expectations of his day. He lists what she is, infers what she is not, but speaks of the fact that he finds her extraordinary, and declares (as one source notes) that "beauty is in the eye of the beholder."
Sonnet 29 is a favorite. In this, the speaker looks at his life and hates it. He has poor luck, he doesn't have friends, he would like to be better looking, and he "despises his fate." However, with line nine, the poem's mood changes completely. The following lines signal a new awareness the speaker has:
Yet in these thoughts my self almost despising,
Haply I think on thee…
The speaker is reminded of the woman he loves, and—in the richness this brings to his life—he would not change places with the most powerful of men.
…that then I scorn to change my state with kings.
Sonnet 73 refers to the common experience of aging. The speaker first describes the time of his life by comparing it to the fall of life. He goes on to discuss the difficulties of the changes life brings, but then addresses the one he loves and says that this should not be a time when the person aging is brushed aside.
Rather than being repulsed by seeing the force of age exact its toll, the narrator says that this should spur his lover to embrace him more fully and urgently...
Sonnet 18 praises the speaker's lover, makings comparisons by referring to nature's beauties, and stating that this praised-lover surpasses the loveliness of the natural world. Because of who the lover is, and because of this poem in honor of the lover, the speaker states:
But thy eternal summer shall not fade.
The speaker promises that this tribute, by way of the sonnet, will guarantee that this lover will live on after his death, immortalized by the speaker's sonnet.