O my wayward heart, I had something to say to you, but by whose influence did you then fall in love with someone else's beloved?

This couplet is a gentle, questioning look at our own minds. The speaker wanted to have a heart-to-heart, a serious talk about something specific. But their mind, described as 'free-spirited' or 'a wanderer,' has already gone off on its own path. It's almost like the mind has secretly fallen in love with someone new, a 'stranger' or an unconventional love, without consulting the speaker. The speaker is left wondering, 'My mind, you're so independent! How did you manage to find this new, perhaps unexpected, love all by yourself, and through whom did you make this connection?' It's a sweet, relatable moment of introspection about our mind's independent will.