As someone with some experience in long-term relationships (ltrs), this is just something that happens in the course of things. You guys met and had an intense experience getting to know each other, falling in love, and exploring each other's bodies. It was a rush, I'm sure, and I'm sure you were having sex often. But now you have gotten to the plateau part. The initial rush subsides into a more general, background warmth--and you have sex less. Once you get to 2-3 years, your relationship transitions into something else, an ltr. This is just how it works. You can't sustain that initial rush forever.
So, as I see it, you have two options. 1) You can keep that excitement going by not getting comfortable, by continuing to make yourself desirable. Don't look needy or desperate for sex. That didn't work when you met her, and it won't work now. Just think about what it is that attracted her to you initially, and do that. Seduce her, but don't vocalize your intentions. If she shuts you down, don't get pissy, just try again.
2) You can break up with her and start a new relationship with someone else. It will give you that initial "rush" that you crave (which, btw correlates with having tons of sex). There really is something about having sex with someone new that is just fun
Yeah a part of me thinks she's more attracted to the guy she met, which was more of an arrogant dick, but in a fun way if that makes sense. But I haven't been like that in a while now that I've become a serious boyfriend. I'm starting to think if I ignore her more, and I'm not that nice/kind of mean she will want to have sex with me. But if that's what she's attracted to I'm not sure what that says about her.....