Though this poem has a slightly casual feel to it—the subject matter and tone is relaxed and content—it's actually pretty formally buttoned up. Your eye will immediately catch the fact that all the stanzas are the same length (four lines each, making them officially quatrains), and after reading one or two, you might also pick up on the rhyme scheme. Each stanza follows the rhyme scheme ABBA, meaning that the first and last lines rhyme with each other, and the second and third lines rhyme. It's like a sandwich—the first and final lines are the bread, and the second and third lines are the filling. Hopefully, if Wilbur is deft with his rhyme (and we'd say he is), the scheme makes you hungry for more. Let's look at the first two stanzas, so you can see the pattern in action.
In the first stanza, "carrel" of the first line rhymes with "Apparel" of the fourth line (these rhymes are the A's in ABBA). "Page" and "cage" which come one after the other are the B's in the ABBA rhyme scheme.
In the second stanza, we get an entirely new set of rhymes following the same pattern. "Bed" in the first line rhymes with "head" in the fourth. And "gloves" and "loves" make up the middle rhymes. The pattern continues perfectly throughout the entire poem (go ahead and check it if you want to).
If you look at the left margin of the poem, you'll see that all the first words of the line are capitalized, even if they aren't beginning a new sentence. Back in the day, that was the unstated rule for all poems. Nowadays, and certainly when Wilbur was writing this poem, the rule fell to the wayside, and poets were (and are) free to use capitalization at the beginning of the line or not. Wilbur usually sticks to the old-school method of capitalization to keep it formal and consistent, we suppose. So while the poem is written in a relaxed and conversational style (with the exception of a few tough vocab words), its formal structure keeps it from getting too casual.
That formality provides a pretty sharp contrast with the laid-back love affair going on in the content. But this love is serious stuff, folks. The regularity of the rhyme pairs in the poem underscore the pairing (not those ruddy pears) of the couple that is the poem's focus. At the same time, the formal structure reminds us that all this lovey-dovey stuff is worth serious treatment through poetry.