Y'know Kri5ty I had exactly the same thought re single parents. As it is, with me doing all the night feeds and OH being full time, it is knackering, and I cherish the weekend when it's the two of us looking after him, so how single parents manage I don't know, especially if they have more than one.
I know it's hard but try to have a nap when your OH takes him. I only do it once a week- the other times I do jobs or try to stay in contact with people- but my Saturday avo nap is bliss.
I totally agree with mopsy though; as a general rule I shower daily, as I think it's important for body and mind to do so! Often we get up at the same time as OH, but if not, I'll put LO down- if he cries for a little bit then so be it. So definitely don't think you're a bad Mum!
It's crap isn't it Oi- you give birth to the little efforts and yet they're still constantly attached to you. Again, may I nominate the authors of the Purple Book for an extremely large haddock. I'm sure we'll look back in a few months and forget it was ever like this...
The one thing I'm finding now which is a lifesaver is that LO is quite content on his mat, or in front of the TV, for 20 minute stretches, and you can get a hell of a lot done in that time. Plus, as wiser souls on here advised, you can get loads done outside the home as they tend to be contented in the pram or sling.
But yeah, house-sitting, that is a crazy thing to do 
On the good news front, tomorrow's lunch is brie sandwiches!