A new study found that over the course of a long-term relationship, a woman's sexual desire for her partner drops .02% every month.  Not for guys, though, we stay the same.  So you're not to blame, guys, if she has a headache tonight.  There are some things you do, though, that are absolute mood killers.  I'm sure women can add to this list, but here are four:

1.  Ignoring her appearance.  You stop noticing how she looks, which lowers her self-esteem.  A few simple compliments every day helps.

2.  Putting her under pressure.  Stop questioning whether she has been "fulfilled" in bed, this only puts pressure on her.  Relax and let whatever happen, happen.  

3.  Using porn as a benchmark.  Keep it hot, but keep it real at the same time.  What you saw in that video may not be safe and satisfying...and she's probably not into it anyway.

4.  Leaving her lips hanging.  A woman's desire doesn't operate like a light switch, but more a dimmer.  So small acts of intimacy, like a hug or kiss, can get her in the mood.