I'm not much of a love poem person, but after reading that entire thing, I have to review it! First of all: wow. That was long. When you sat down to write this, you must have been willing to put a lot of time into it, which is always a sign of good poetry. I love how you go all metaphorical in the last 1/4 of the second stanza, producing the title. (Or at least, I'm pretty sure that's where you got it.) "I will tread carefully on the highways / and maps of your torso..." - great job there! My favorite part, however, is the first two lines of the poem, the italic ones that you also used for the summary. They make quite a nice couplet.

this is just lovely.
the first few lines... are faltering, they are almost too much for the tongue -

you grabbed my hand once,
in the middle of the night and you
held it tight and I don’t know if you
were asleep or not but I wondered what
you were dreaming about, because
I was dreaming about the wrong things.

- a long, long beginning, 'you' and 'you' and 'you': this establishes the vocality of the poem perfectly.

you noticed that my walls were four different colours.
- you balance the mundane with the abstract very well (!), and I love the way you use patterns and places: Picasso/ the portrait gallery

- cricket, 'bat and ball games': it has a summery, lost feel, as if you're sieving through your childhood and deciding what to keep and what to throw away

- I love, most of all about this poem, the way you (sorry for the cheesy expression) seem to zoom out from just the girl and the boy: the dutsbin men -

do they suspect, ever, or even think, that a few metres up there are
people lying in each others arms?

- and involve other people: the hundreds that have asked you to check tickets, that you pass in the street...

here's something lovely:
"thousands I see, thinking of one."
read fado, by edwin morgan. he's my FAVOURITE.

can I say something mildly critical? it's almost too long. a few ideas are repeated, maths, ball games, learning and the sense of possession of the boy. it could almost be refined...

a beautiful poem.

"I was dreaming about the wrong things." Cheeky :P