According to a new study in "The Journal of Sex and Marital Therapy", women in committed relationships lose their sex drive faster than men . . . which isn't that surprising.

But the study measured it, and the average married woman loses about 0.1% of her sex drive every six months . . . or somewhere around 1% every five years.

So guys, it's in your own interest to keep that from happening. Here's a list from "Men's Health" of four things men do all the time that can completely kill a woman's sex drive.

#1.) Ignoring Her Appearance. According to sex counselor and author Ian Kerner, quote, "Guys in long-term relationships tend to stop noticing when their partner looks pretty. And [a lot] of female sexual desire is tied to [her] self-esteem."

Kerner says giving a woman compliments on a daily basis, and letting her know you still think she's sexy makes a huge difference.

#2.) Putting Her Under Pressure in Bed. Some guys get obsessed with whether the woman was satisfied or not, and it's usually more ego-driven than anything else.

But what happens is, you end up making sex seem like a TASK . . . which takes the romance out of it. And it can make it IMPOSSIBLE to satisfy her. That's one of the reasons so many women end up faking it in bed.

#3.) Using Porno as a Benchmark. It might help keep things exciting, but it definitely shouldn't be what you're STRIVING for. Most of it's made for men, and includes stuff women just aren't into.

And obviously, asking for something she thinks is GROSS is the easiest way to turn her off.

#4.) Not Enough Foreplay. Guys look at foreplay like it's a light switch: They think a little kissing is fine . . . then they move on to OTHER things. And they almost always move on too soon.

Guys also think of foreplay as something that ALWAYS leads to sex . . . which it shouldn't. A hug or a big kiss every now and then can go a long way.