Well then...its not about the quality of sex...but about something else she isn't getting from you....ie: watching The Cougar. She wants to *feel* a certain way about herself, via her interpretation of how her man feels about her...and somehow she is not getting that from you.
I'm still saying its her issue, not yours...but she is unfortunately projecting it upon you.
And for whatever its worth...I'm sure the quality of sex is good, but its something deeper yet intimately related to sex that she is missing, and blaming it on you. She has the typical female misperception that since she feels something lacking with you, that its your fault and you should *just know* what she needs. So its the sex...but not really....
Yes, its the "it" that is the problem, and she fears it will be there forever and ever...because she isn't used to the idea that it might possibly be her issues that are causing it.
So please try to hear what I said, but think of it in different terms...its not about the quality of sex. It rarely is about that. Its about the quality of the passion and the connection, and her feeling desired and pursued. She won't be able to live without those things, but you shut down and stop pursuing her when she stops giving you sex. The "it". I do understand. I'm hoping to create a small space in your head for yet another possible angle to look at it with.