A lover comes complaining, and the speaker answers with a shrug. She admits she loved him on Wednesday, but that was then. By Thursday, the feeling is simply gone. The poem’s wit comes from how calmly she refuses to treat that change as a problem. To the man, her Wednesday love apparently meant a promise; to her, it was just a fact about one day.
The speaker is not cruel or heartbroken. She sounds almost amused, a little impatient, and completely free. The repeated “what is that to you?” and final “what is that to me?” collapse past and present into something small and distant. The mood is light, sharp, and a little cold: a love so brief that it barely leaves a trace, even on the person who felt it.