Yup, game still matters. Women stay women. That which attracted them at the beginning is still attractive years down the road. Trick is, you gotta adjust the game. It's not for picking her up, it's for keeping her. Same kinds of things you did before, but now you gotta learn timing. You just can't use some of it as often as you once did, or it gets irritating. Some things you need to do more. trick is, now you gotta learn phase 2 of the game.
Don't wanna be used? Then be stronger than her. Not physically (hey, I dunno, she may be a powerlifter), but don't let her walk on you. You're your own man. She's a gf, that means you are still independent even in a committed relationship. Do NOT confuse that with stepping out on her. Be faithful (unless she's cuckold or a swinger, but that's different). Walk as if she left tomorrow morning you'd have a hotter women in bed tomorrow afternoon...or evening depending on when you get up...lol You don't threaten her with it. You don't suggest it. It's a strictly internal thing. CONFIDENCE. If you were married, it would be different, but game still applies, even married.
If she starts using you, make her gone. Or, just be strong enough not to be used. Read the Gor books, and then figure out how it applies to modern real life in the 21st century. The philosophy is sound (mostly), it just needs some heavy adaptation to fit within laws, the dynamics of actual people and such. Good starting point, tho.
Basically, be the slick dude that picked her up and talked her out of her panties. If you want to keep her, you gotta go deeper than that, but you need to still be the slick, confident mofo, that bagged her at the start. Just be a responsible, caring, slick mofo.
If she sees you got game (don't expect her to ever admit it...ever), then she'll know she's gotta work to keep YOU, not the other way around. If she just wants to control you, drop her fast, but don't be nasty or vindictive. Just be straight up and honest.
The advice my wife would give you (and has given other men) is that if you let her think she's in charge, she'll eat you alive. You'll turn into a Scorp skin welcoe mat at the front door. My wife is a bit sexist...lol. But seriously. Just be the strong, confident slick guy she met. Don't be slick all the time, but often enough that she knows you still got it (again, don't expet her to admit it).
And tell her "No" from time to time. You're the man, BE the man.
CJ