It's not very vague at all. You don't need to explain your situation. The 1 year mark is a very common point in which relationships start to get old. You get into a daily routine; missionary sex at night, breakfast in the morning, weekly dinner out, etc, etc. The list goes on.
How do you light that spark that was once there? It's very hard to spice up your relationship all the time. But you do need to have moments every now and then that remind both of you why you are together in the first place. Whether it be a great night out with friends, or a great night of wild sex.
Try doing different things. Instead of going through the same routine, try to switch things up a little bit. If both you and her are doing new things, there will be new reactions to everything both of you do. Things aren't as predictable. Women don't particularly like predictability, no matter how much they say they do.
Seeing her a little less is also an option, but be careful no to distance yourself too much. This just adds to the fact that you two are growing farther and farther apart.
Most of all, think of how you two acted when you first started dating. Think of things you did back then that you no longer do. DO THEM. Whether you tell her or not, just do them. After a year some men feel that they can settle down and just take it easy. This is rarely the fact of the matter. If your woman is a quality woman at all, she will demand at least a little bit of excitement every now and then. Best of luck.
