Can anyone give me the meaning of Sonnet 51?

(Continuing from Sonnet 50) This is how my love for you excuses my horse’s slow plod as I journey away from you: “Why should I hurry away from you?” Until I return, there’s no need to rush. But what excuse will my poor horse have for his slowness then, when even the most extreme swiftness will seem slow to me? On the return journey I’d use my spurs even if the animal rode like the wind. Even if my horse had wings I’d feel like we were standing still. No horse could keep up with my desire then. My desire, made of the most perfect love, will race toward you like a horse made of fire, not neigh like a slow, dull horse made of flesh and blood. But, my love, out of love I’ll excuse my horse like this: Since he deliberately went slowly as he was leaving you, I’ll run back to you and forget about the horse altogether.