Smurfy,
For me personally, if I hadn't seen my GF in a few days I'd be a little upset if for the one day we do finally get to see each other she acted too tired for me.
Just explain to him you wanted to have quality time badly, but you were just so worn out.
It's like when your friend chops your arm off with a chainsaw on accident. It really pisses you off, but at the same time you know it was an accident and unintentional.