She needs to go see her doctor and he can help her with her apparent depression and lack of libido. When you're not feeling good about yourself (which she seems to not be) then the last thing you crave is intercourse or even bothering with other forms of intimacy.
Has she always been uninterested in sex or did this just occur after she lost her mother?
You're not married you know, if she won't do anything to help herself which in turn would help you with why you're dis-satisfied, then you would be foolish to continue on with someone that you will eventually get bored with and either cheat on her or leave her anyway so why prolong the inevitable?
Talk to her about seeing her doctor and ruling out anything physical or mental or getting help with her despondency.
Hearing about how much someone else likes having sex with their male partner isn't helping your situation any... actually DO something tangible by encouraging her to get the help she needs and if she won't, then get the strength to leave her for being incompatible with you to the point where it will never get any better but only worse.
“The willingness to accept responsibility for one’s own life is the source from which self-respect springs.” ~Joan Didion