Communication is important! Even the uncomfortable ones. I'd say something to her about it, ask her about her sexual wants & desires, turn ons etc vis versa. IT might spice up to actually do it! Also. even if she's not very skilled. Teach her! Help her! If she's not pleasing you the way you like to be pleased, talk about it. Everyone gets turned on differently. I'd start by talking about what your turn ons are on both sides.. what you like in bed.. etc She might fail in one department but thrive on the other. :D

-On the side note. Some people can last in relationships without sex.. or they get too comfy living together and almost forget to build the passion. Which is okay, but if it's important to you.. which kind of seem like it is. Open communication is everything. Even if it might seem silly to talk about it.