It's never a good time to talk about something a selfish person doesn't want to hear. Talk anyway.
A wise man once told me, "Love isn't about what you
feel, it's about what you
do. It's putting the other person's needs first." If you look at it like that, it's not too difficult to distinguish infatuation and other dramatic ridiculousness from a real relationship.
In my case, it looks like buying the abomination known as
lutefisk at a Norsk festival, because she's been looking forward to it forever, but the kiosk only takes cash and she only has cards, and I can't let her be disappointed and embarrassed in public. Laying awake for six hours in an awkward position with a crushed shoulder and a dead arm, hurting for nicotine and knowing I have to work tomorrow, because someone's having nightmares and only calms down with my arm around her. Discouraging rent contribution offers when she stays here, even though she makes more money, because I know she's got a credit balance to pay down, and I'm debt-free.
On the incoming side, it looks like putting herself at risk to save my life on multiple occasions. Spending time with me even though I'm a smoker (17 years and thoroughly addicted), and the second-hand smoke sometimes makes her physically ill. Bringing me things I need but wouldn't go out and get for myself, for budget or time concerns or any other restricting reason.
Figure out for yourself whether you love your partner, and whether she loves you. Decide what you need to do about it, then go and have a talk. It won't be a good time. You need to do it anyway.