First ask yourself why you've been with her this long and was it/is it for the right reasons?Ive been with my girlfriend for 5 years now and she is starting to act like she doesnt care what I do anymore.
Is there anything I can do to get her interest back in me?
Then ask yourself what is the end goal with her?
In ltr's, guys can get complacent, lazy, comfortable. These are all comforting things people can easily fall into and not really think about. There is that security aspect for some as well. However, the flipside is you no longer remain desirable as you let yourself go or do stuff that you didn't before or quit doing stuff that attracted her to you in the first place.
All this boils down to is are you right for her and is she right for you? If so, do both of you know about it or have discussed it?
Don't stay together just because you have a kid together or that she's making your life easy by paying 1/2 the rent and maybe doing other domesticated duties for you. That's not a good reason.