Men are expected to be yearning/aching/wanting/thinking about sex every waking moment of every day. Which, we guess, is why the authors of "He's Just Not Up for It Anymore" say women jump to some pretty drastic conclusions about why their men don't want to do the deed.

Here are a few:

1. He's angry.
2. He's not well.
3. He's been traumatized.
4. He's addicted to porn/drugs.
5. He's cheating.

Yikes. While those reasons may, in fact, be valid on rare occasion, we've got a better idea why he doesn't want to jump our bones: He's tired. Read more of this ground-breaking theory after the jump.

Think about it: Sex for gals isn't a wham-bam-thank-you-ma'am kinda thing. First, he's gotta convince us we actually want to have sex. (And let's be honest -- we use the "tired" excuse waaaay more often than dudes.) Then, he's gotta warm us up. Then there's foreplay. More foreplay. Even more foreplay. Then finally, sex. It's a process.

Now throw in an awful day at work, a mind-numbing hour-long commute during rush hour, kids (if applicable) and dinner. Perhaps, like us, he's just exhausted. So instead of spazzing that are men are banging their secretaries just 'cause they don't want want to get kinky tonight, give him a break. Or a blowjob. Either way, he'll appreciate it.