@rydinearth,
Ouch, Carrie has given such good, and such bad advice.
Your short introduction suggests you suffer from 'nice guy' syndrome, where you try to please people.
Your issue appears to do with
not being true to yourself, probably because you been lead to believe that doing so is selfish.
If you can't be true to your own needs, your own wants, your own views, your own beliefs etc...if you don't respect them, then why should your wife/partner/girlfriend?
If you don't believe in yourself, why should your girlfriend? Your self belief while you are interacting with her is a reflection of how you react to the world. If you are giving in to her to 'please her', you will do the same to others. Contrarily, this idea does
not please her.
If you can't create your own world/reality (something that you believe in, and are true to), then you will inevitably reside in your girlfriends world/reality. This means she has to create a world for two (rather than you both creating a life together)...which drains her of energy. This trait is otherwise known as being clingy/needy (my own belief is that this one particular point - about creating our realities, and it's implications - is why nice guys finish last)
The greatest gift you can give her...the most romantic moments you will ever bring her...will be something given and done from the absolute heart of who you are...without a single string or need for love attached. That can only come from a strong/deep sense of self, which only develops through being true to yourself.
I would suggest 2 books that I found very useful. "The way of the superior man" by David Deida (which btw, is not about being superior, but about being true to yourself), and "No more Mr Nice Guy" by (well, I can't remember who by, and I can't find the book atm, but again, is about being true to yourself)
It is 'who you are' that should please her...not what you can do for her.
The second book actually makes the claim that being a 'nice guy' is deceitful, and that bad boys are actually 'more honest about their wants and needs'.
My own thoughts on the topic are here (if you can get past the use of the term 'selfish')
http://able2know.org/topic/129648-1