Why did the wife leave the merman in "The Forsaken Merman"?

The poor merman and his children are confused, upset, and isolated by their sudden abandonment by Margaret, the merman's wife. The merman is unable to move on with his life as he simply can't quite get his head around his wife's rationale for suddenly taking off to the town. Mired in grief, the merman is so upset that he's effectively lost all track of time. Hence his constant refrain of “Was it yesterday?", meaning was it yesterday that Margaret upped sticks and left her family.

But the reasons behind Margaret's departure are not really that hard to discern. The truth of the matter is that she no longer wishes to lead the kind of dissolute, free-spirited lifestyle that she has been leading with her husband and children. In simple terms, she's growing up, which is why Margaret's actions have been interpreted as a metaphor for the often difficult process of making the transition from childhood to adulthood.

That said, leaving behind her family has not been easy for Margaret. She throws herself into her work at the loom so that she doesn't have to think of those she left behind. But even so, there's no going back, just as there's no going back to childhood from adulthood.

In Matthew Arnold's poem "The Forsaken Merman," the speaker addresses his children, who are calling out to their mother, Margaret. Margaret lived with the merman and their children under their sea, and their life seemed to be a happy one. However, she heard the church bells tolling from the land and was reminded that it was Easter. She said that she had to go to the church to pray with her family, as she was losing her soul living under the sea with the merman.

The merman told his wife that she should go to church and then come back to her family. She went, but did not return, leaving the merman pining for his wife and the children for their mother. Since the poem is in the merman's voice, Margaret's feelings and motivations are never entirely clear, though it is evident that she is emotionally torn between land and sea. The reader does not know whether she always intended to stay on the land once she reached it or if she was persuaded to do so once she arrived. It is also uncertain whether her motives were primarily religious or secular—whether she thought she was losing her immortal soul by staying away from church or if she was made unhappy by separation from her own people.

What work occupies the merman's wife in "The Forsaken Merman"?

Matthew Arnold's 1849 poem "The Forsaken Merman" deals with feelings of loss and isolation. Margaret, the merman's human wife, who once lived with him happily beneath the sea, has left him and their children. One day, she heard the bells of a church tolling and leaves to go back to the surface to pray. The merman assumed that she would soon return. However, she remains on the surface to live and work in the seaside town.

After some time, the merman and his children go ashore to retrieve Margaret. They find her busy praying in the little grey church. Although the merman begs his wife to return, she does not even look up from her prayer book. The merman and his children return to the sea, but Margaret stays behind, where she continues to pray inside the church. After they leave, Margaret stays in the town and keeps busy by spinning yarn at a loom and singing joyful songs. There are moments when she puts the spinning aside and gazes out at the sea. However, it is clear that she feels she must stay in the town and work her loom rather than return to a life with her enchanted family under the waves.