808s & Heartbreak has 11 songs which are about Kanye West's broken heart thanks to his ex-fiance and the final track Coldest Winter is about his deceased mother Donda "MomYe" West.
Back to the song with Wayne, See You In My Nightmare is a song proclaiming the hurt that the artists feel thanks to the respective females. There is a line where they say "see you in my nightmare, how the hell did you get there, cause we were once a fairytale . . ." Enough from me, enjoy the song on your own.
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Kanye West ft. Lil Wayne - See You In My Nightmares