Before the Sea

First, my rendering loosely based on yours:

He walks away with me
my arms encircling,
kissing the summer in his hair.
Delight engulfs at treasures –
waiting, discovered,
picked up and placed in pail.
He pauses, staring at the broadness of the sea;
his speck before the vastness –
worlds, adventures, unimaginable.

Little one, the sea is before you.
The sea is within you.
The sea seeps from my eyes.

However, you have to do it YOUR way, as your writing. So let me just point out what I see, working from YOUR rendering.
"He walks away from where we’d been,". It is redundant. Of course, we always walk away from where we've been. You might as well have said that you walked toward where you were going. The question is whether the redundancy adds to the write - does it give it a style, improve the cadence, provide emphasis (as in Poe's repetitions in "Ulalume" (or "the sea" in your last 3 lines? I honestly don't think it does. If it adds value to the poem, you could describe what he walked from, but I don't sense that will add anything to the poem except words - not a desirable thing.
"Delight overwhelms as he discovers waiting treasures". Actually this isn't a bad line, and it's not necessary to explain whether it overwhelms you, him, or both. I just think the same thought could be expressed in fewer words. That translates into greater impact. By the way, I did forget to compliment the 2nd line.
"For just a moment he pauses, looking out over the broadness of the sea –" "For just a moment" can be expressed with far fewer words. "For" is totally unnecessary, and doesn't add to the write. Ditto the other 2 prepositions - out over.
I don't want to do more than give you an answer to your query. These are a sampling of what I mean by wordiness. The thoughts are wonderful - IMHO just need to be expressed more crisply.
I hope this is helpful to you.
Alcuin