It is telling, I think that when Nenita is first introduced, she is described as "the wife." She is not the loving wife, the dutiful wife, the good wife: just the wife. Earlier, she'd taken a nap that she hadn't meant to take. We learn that her husband's siblings had spoken down to her, criticized her, but they are mostly dead now. She continues to pray for their souls but she isn't sad that they're gone. She has lots of work to do—rice cakes to make for an order, a tea to make for her hungover grandson, her husband's medicinal tea—and so she gets to it. She hears her husband singing at a party, even from her home, and she really cannot understand the big fuss over his singing. It makes her happier to listen to him talk about music with her grandson.
In other words, it's a life. Nenita neither feels extravagant love for her husband nor hates him. He's unfaithful, and she goes about her life. He takes the money his relatives sent for his medication and spends it with another woman, and Nenita goes about her life. She seems to be relatively contented in her sphere, and so she continues in it. She even has the means to poison him and escape this life, should she choose to do so, but she knows she never will. She is content, and she lives life on her own terms, and this is good enough for her.