Sadly, the inconsistency of this poem lets it down. The rhyme scheme alters from a standard ABCB and variates throughout, making the flow jolt a bit. I got from first reading that the perspectives are joint? Like male - female alterations? If not, then this poem needs some serious altering itself. There are some nice lines that stand out that I won't bother to copy and paste, but, like I said earlier, the poem remains inconsistent and some of the wording is a bit hit and miss, and some of the rhyming is a bit forced. Not sure if 'tears' and 'stairs' rhyme..
I'd have liked it if you'd used flashback to show the persona the current situation, as it simply reads like a poetic rant of loss and heartbreak, which could be written by a troubled teenager. As I said earlier, there are some nice lines, but they're let down by too many things said too many times in too many other poems.
Admire the length of the write, but could be better.

Thank you for taking the time to do this collaboration with me. It was a lot of fun as always. ;)

Peace, Joe