Shakespeare went beyond the boundaries of epithalamion in his play "A Midsummer Night's Dream." Act 5 of this work, as Harold Bloom in "Shakespeare, the Invention of the Human," notes, shows both irony and sarcasm in the progression of three royal couples toward consummations, as they watch the Mechanicals perform "Pyramus and Thisbe." The wedded couples comment wickedly throughout the scene; Shakespeare presents newlyweds as the sources of disquiet and criticism. The Mechanicals' selection of "Pyramus" -- a myth in which lovers die in a suicide pact -- is also questionable, and, as Bloom suggests, the lack of characterization of the lovers seems to mean that their love is arbitrary and fleeting. Shakespeare imbues even bridal poetry with irony.
Edmund Spenser's "Epithalamion" is an emblematic wedding poem; its structure, as Max Wickett comments, is Spenser's attempt to "create microcosmic models of macrocosmic order." This small world of the wedding is highly structured and ordered, notes Kent Hieatt, in accordance with the hours of the day and months of the year. Spenser may have felt the need for such obsessive structure, since the poem was written for his marriage to Elizabeth Boyle, an Irishwoman; its cosmic orderliness masks some rather troubling ideas to be found in the poet's pronounced anti-Irish sentiments.
After reeling off some 200 lines of elaborate poetry to emphasize his bride's beauty, Spenser speaks of their marriage as one to "raise a large posterity ... from the earth, which they may long possess, up to your haughty pallaces may mount ... of Blessed Saints for to increase the count." His wife, in other words, will become a baby-maker, creating Englishmen to supplant the Irish and make them all "Saints" -- kill them off and take their lands. According to his biographers, Spenser published anti-Irish pamphlets with anti-Catholic sentiments; he ultimately fled the destruction of his estates by an Irish mob, escaping to London and his premature death. Ironically, legend has it that "his wife also died" in the burning of his castle at Kilcolman. In the poem about his wedding, the reader can find the seeds of the poet's destructive beliefs.
Not all epithalamion poetry can be connected to such unhappiness, but the two greatest writers of this genre wrote of it with irony. Spenser's is perhaps unwitting; Shakespeare is all too aware of it. Apparently England's best poets could not approach the genre with anything like pure and innocent sentiments. No significant modern English epithalamion poetry is extant, but it's worth noting that contemporary American author e.e. cummings created "Epithalamion," a poem filled with classical imagery juxtaposed with sexual reference; it also hints at the destructive power of libidinous matrimony.