For whatever reasons she's decided to take a step back in the relationship. She doesnt sound like she's ready for anything. If you've already proposed twice and she's turned it down, and now she's taking another step backwards, maybe you should also evaluate the relationship. I dont think she's trying to manipulate you though, you've aleardy proposed, she's had the golden question asked, which is what some women want and or need and manipulate to get! I would throw that theory out the window. She doesnt need to manipulate you into getting anything she wants, cause it sounds like she's stepped back a few notches in the relationship.
Maybe she is genuinely wanting what's right for both of you. Starting the pre-marital counseling is a good thing. Understanding why she took sex away is another, but knowing myself as a Christian as well, we know pre-marital sex is a no no. Maybe she just found her beliefs again, and is feeling this is the way its suppose to be. I really dont know, just an idea. But you have to talk to her and let her know how you feel. Obviously youre sexually frustrated which turns into other things. If you dont talk to her, this could cause some permenant damage to your relationship. If this is someone whom you've proposed to, then you should be able to trust her to take what you say seriously and consider your feelings as well. I dont know how you can compromise "those" kinds of needs, but I'm suggesting talking to her and letting her know exactly how you feel. This is something that needs to be addressed before another proposal. But keep an open mind when discussing these things with her, she may have legit reasons in her own mind, and she must be willing to be open to you as well.
Goodluck!
everything happens for a reason...beginning to wonder why.