Talk. To. Her.
I swear, what is it with guys and trying to solve relationship issues without even consulting their girlfriend/wife/whatever? I'm not the authority on relationships, but I can tell you this; if there is something wrong and that is bothering us, most likely we
do want to work it out and talk with you about it; we just feel like it would probably be a waste of time. At least in my experience, when a guy wants "to talk" about a relationship issue, what he actually means is, "I'm going to talk, and you're going to listen and agree with me." This is not how it should go.
If you really care, and you really want to do something about it; ask her to talk. You may have to coax her a little, gently of course. If you can get her to agree to this, you've already got your foot in the door (probably). You can explain your feelings and thoughts on the matter, but be damn sure you're telling the absolute truth, and not just what you think she wants to hear. Also make sure to listen to her thoughts as well, and take them into consideration, even if they directly contradict yours. Be willing to compromise, and if you make any promises or changes, you had better intend to stick with them; we tend to remember your exact words quite well.
Sometimes, an unstoppable force meets an immovable object. Sometimes, you can't fix everything. Sometimes, these things don't work out, no matter how hard you try. If possible in this situation, it's nice to remain on amicable terms, but if this isn't going to happen; cut your losses, and move on. You need to have a good head on your shoulders, enough at least to understand when an uphill battle becomes a lost cause. There's no sense in chasing someone who doesn't want you, because it will only cause more hard feelings and heartache in the end.
Again, I'm no relationship expert. But I am female, and I hope I've provided a little bit of "insider information" (though it really should be common knowledge, honestly) to help you out a bit. Good luck.