the boy i loved

[dukealien]

the boy i loved, he sang for me  see comment below on punctuation
i danced and smiled happily
the joy i had could not compare  needs basis of comparison, or the (somewhat stock) concept "beyond compare," perhaps
i've searched for it most everywhere

the time we shared could not be priced  switch from end-rhymes to near-rhymes (see below)
the seconds we had made my life
but like all good things, we would fade
his song would cease, my heart would break

i cried and wept, "my musician!" an added foot in here could make reading smoother - "my own musician" or the like?
he was gone, left on a mission rhythmic carry-over from last line
i wished him well, i said goodbye
he didn't look back, but i heard him sigh could do with a few less beats on this last line, perhaps

In intensive critique (or a little less intense than that)...

In general, while consistent meter is not required it tends to accompany rhyme.  The second stanza, for example, speaks of conflict and uses near-rhyme instead:  broken meter can work there.  But in the first and last stanzas, which are rhymed, a regular meter seems (to me) a better fit.  (I'm tempted, for example, to read L2 as "I danced and smile-ed happily" to fit the meter L1 seems to establish.)

In the area of typography and punctuation, the choice of no capitalization is yours and works fine.  However, the choice of no punctuation at all for line endings is not helping.  For example, L1 and L2 are logically connected but separate statements.  A colon at the end of L1 (or an em dash) would help the reader who otherwise tries at first to read L2 as a continuation of the sentence from L1.  Use of commas within lines is inconsistent with no commas (or other punctuation) at line ends, though consistency is not mandatory, either.

Some expressions are near or over the line into cliche - "all good things" and "wished him well" are examples.   More originality is a plus.

A final suggestion:  lose the final sigh.  The rest of the poem is about the narrator's feelings.  Bringing in those of the beloved here, even by implication,  is a little late for this turn, in my view.

You've told a simple story - with a few inventive flashes of language and regular meter where appropriate, it could be better and more striking without sacrificing that simplicity.