The speaker describes a split inside themselves. The sensible, adult part of them knows that something is over, and wants to leave it that way. But their "inner child" has other ideas. She picks up the phone on her own, "without my permission," and begs to talk to someone who makes her laugh. We never learn who that person is, though the poem suggests a relationship that has ended or should end.
The last two lines carry the poem's emotional weight. The speaker says they "explained about endings," as if reasoning with a child, but the child answers with something simpler and harder to argue with: love. The feeling is a quiet tug-of-war between head and heart.
The mood is tender and a little rueful. The speaker isn't angry at the child. They seem tired, maybe sad, and perhaps secretly moved by her stubborn hope. The poem leaves open who is right.