Insideout, THANK YOU for this post. *bows*
Tigerlily, I have your problem down to the t. I am naturally an organized (though not necessary sparkling clean) person when it comes to my living space. I grew up that way---both my mom and grandmother are very tidy people. My mom's house is covered in dust, but by god there's nothing out of place!

And to be honest I like it that way myself---I function better that way.
My bf, unfortunately, is not. We live together. And while he's not gross like most guys, he will let donut boxes and empty 2-liters litter the floor for days. Also he is obsessed with clothes (he used to be obese, and lost a ton of weight), so he's always buying SOMEthing (he is very thrifty, though, so it's always for cheap). We have a bedroom we're not even using because 1) It became our clutter room for stuff we don't know what to do with, and 2) This winter we had a mouse problem and they cohabited in that room.
Long story short there is always ***** EVERYWHERE. It gets so overwhelming. Bf works 12 hour days 6 days a week, so it's up to me to clean, and I've been a borderline basketcase off and on for months. I'll get a wild hair and clean the bathroom/livingroom to tiptop, then it all falls apart again in a matter of days.
I have yet to really figure out the solution. Once the bedroom's cleaned out that will help enormously, but that takes him and me working on it.
Otherwise when I can clean/up to it, I crank fast/hiphop/rock music (I make a playlist on Youtube) and it's amazing how much I get done while the songs play.
But yes, it is really hard when it's just you anyway, having absolutely no motivation. I used to live alone and I struggled with that (like the kitchen, having no dishwasher, will not elaborate).