As he got older, the boy would have one main image of his father in his memory

The boy was woken up by a light late one night

He wasn't really awake and it looked like his dad was holding fire

It was really just because he'd lit a match to check on his son

But he held his hand curved around the match and the light was his love

And the curve of the hands looked like a heart

So his son felt like his dad had revealed his real heart

And the love there was too powerful to bear

On his dad's face, the love was too intense -- it was best seen when half awake in the night

It only lasted for a moment

But the son knew it was there forever after

I think that any paraphrasing of a poem comes down to what the reader feels about it.  In reading this poem, you might want to ask a couple of questions that could help you determine what the meaning of this poem is to you.  The first would be to discuss the relationship held by the father and son?  Is there love present?  If so, it is openly demonstrative, or one that is a bit difficult to express?  Do both know how the other feels about them?  (Keep in mind that the poem is constructed in a series of rhyming couplets, so as one line is spoken, its counterpart is heard afterwards.)  Another set of questions to ask is about the nature of the title. Under what conditions might love be seen as a secret, or something that can only be understood by two people?  The reality is that in paraphrasing the poem, it has to be done by you.  It seems artificial for anyone to give you a line by line paraphrase because that is what the poem means to them and if you have to paraphrase it, the best one can do is to give a series of guiding questions upon which there can be reflection as you read it.