The poem is about a breakup, or at least the wish for one, and the uneven way two people let go. The speaker is sure of one thing: some part of him will always love them. That "always" sounds both comforting and heavy, as if the love can't be switched off even when it should be.
The speaker's own side is less certain. Only "a part" of them will "try to unlove" him, and the word "try" gives away how hard that is. They aren't promising to succeed. The epigraph, "Love unlove," sets up the tension: love is something you do, and undoing it is a task you have to work at.
The short lines and wide gaps make the poem feel quiet and hesitant, like someone speaking carefully so they don't say too much. The mood is sad but restrained, a mix of tenderness, regret and stubborn attachment that doesn't resolve.