Is she purposely tempting you? I think that's an important thing to clarify...
MissCriss beat me to the crucial piece of information.
Is she purposely doing something to tempt you? Then you're going to have to stop seeing her. Being around someone who insists on acting in such a way is only going to cause you to fall.
Or, are you being tempted simply because you have a significant other paying attention to you? That can be a problem for a lot of people as well. The other person might not be doing anything on purpose, they're just there and paying close attention to you that you're not usually used to and so it ignites all these other feelings.
If that's the case, I'm on board with the others here who have advised to talk to Christian mentors, because this happens to almost everyone. You might need to start restricting yourself to only spending time together in public or in groups.
Which will cause people to protest with, "Why would two grown adults need a chaperone," and the answer is, if you're close to disobeying God, and continually put yourself in situations where it's possible to cross that line, putting up guards is your only other option, aside from ending the relationship.