I agree with mskc0511.
If sex is your only priority then you should really dump her and find someone who can satisfy your sexual needs.
I know that sounds harsh, but if that's all you want from her- and your'e obviously not getting it-then you then you need leave her alone.
Don't pressure her into having sex with you, because the more you push her, the more she's NOT going to have the desire to do it.
The other thing is, you need 2 figure out why? she shuts down.
I was raped as a child, and similarly I behave the same way she does. If you've ever watched the Antoine Fischer story that should help you the effects of sexual trauma as well.
Furthermore, you should ask her if she were "traumatized" (raped, sexually abused, molested) as a child and see how she reacts to it.
Lastly, you should understand that there is NOTHING you can do about it because it starts with her and she should be the one to make the change- but I guarentee you, you'll only be making it worse if you push her.
It does NOT mean she's a lesbian, unless she shows any interst in females.
Besides, you don't know weather or not she's shutting down sexually because you're a guy (which I doubt), or for some other reason- which is why I encourage you to find out if she has an underlying motive. GoodLuck[/code]