The speaker is in love with a close friend and hasn't told him. They suspect everyone else has guessed, but he hasn't a clue. The whole poem circles one worry: if the truth comes out, will the friendship survive? The speaker wonders whether the "best friend / Love" they share now would stay the same, or whether he would simply brush them off and walk away, leaving them "aching, longing."
The layout adds to the feeling. The lines are pushed across the page, and a few words sit stranded at the left edge: "I," "Think," "Want," "Love," "Him." Read down that edge and the poem's emotional core shows through, almost like the speaker's real voice breaking out of hiding. The mood is anxious and tender, a mix of hope and dread. Nothing is resolved. The poem stops with the speaker still wanting, still afraid, and still keeping the secret.