I have tried asking her things such as “Anything I could do to satisfy you more? What do you hope to accomplish by buying things for people, myself included, that we often say we do not need?”. But fact is my g/f can not keep a savings (spends all job money on luxuries) and seems to be constantly flirting and, in the meantime, has no real hobbies (no music, cooking, reading, etc. …just watching movies of non-mutual interest). She constantly mentions having kids but between savings, lack of will to stay in shape (and corresponding frequent sickness), and a short temper I find myself walking “out of the room” a lot and fear she does not have the energy or discipline to raise kids well. It admittedly has become a game of give-and-take: when she continually asks me to, say, see chick flicks for 5 evenings in a row, I say “no let’s go out, exercise, or do something fun or healthy like we used to in our early dating days”. But she’s just not the same how do I get through to her?
You might wonder why I put this under mental health. My theory is, in some way, my girlfriend can not feel useful and is flirting and spending on gifts for even barely acquaintances to feel she has done something for someone when this should happen through hobbies.
The other thing I worry about is could this come down to her own anger about physical satisfaction? I am a half-marathoner and have always made a huge point of keeping my sexual stamina up for her satisfaction but maybe she’s hoping for someone more handsome and/or cocky/unpredictable to keep her emotions sexual and satisfied?
Note I do NOT want answers to this question that state vague point like “communicate better” without saying how or why. You don’t need to be a “doctor” but, please, at least give 500 words or so on the topic (if you have a URL/link, summarize it well). Not to be a nudge but I got secondary school-ish answers last time I tried asking this question. Thanks & best luck answering! 
Another detail…odd as it is she does NOT spend my money at all only her own (that’s why I put this under mental health not marriage and divorce (kind of have to laugh about this)).
And she used to be unbelievably outgoing: giving me massages and my giving her them back, surprising me with poems, taking us to see mutual movies and relating them to what was great about our relationship, trying to cook things with me and teach me about it, and she didn’t have any problem complementing the heck out of me on my ‘loving skills’ (or switching taking the dominant position)…we were a team back then.
One underlying question: why might that have changed (that I can control, or at least make an effort to un-teach her bad habits)?
Had to put this again after someone gave a comment that I spoiled her it isn’t that simple: I DON’T SPOIL HER materially or emotionally.
Everything she buys she buys with her own money and I don’t take her out to dinners or such either and refuse to put my money or time into activities of non-mutual interest as I always have.
I never did these things at any point earlier either: at the beginning, despite lots of long dates, many of the rewards were more like those of a fling than a relationship.
