Lol dude. Seriously. You need to man up before you create a self-fulfilling prophecy. Worrying this much about breaking up will actually CAUSE you to break up.
If I were your gf, I would have broken up with you already!
Ok now I have made you fear, it's time to get on the right track.
I find it suffocating not to ask her "so, how long do u think we'll be together?" and questions regarding the relationship, meanwhile she never asks questions like that.
STOOOOOOOOOOOOOOOOOOOOOOOOOOOPPPP asking these questions. Do whatever it takes to stop doing that, and stop acting like that. You're too needy and overprotective. I repeat, THIS WILL CAUSE THE VERY THIN YOU DON'T WANT. Whatever you do, stop doing that.
The other piece of advice I'm going to give you is DUDE, seriously, stop with the fucking "game". Stop playing hard to get and stop "gaming her". YOU'VE ALREADY WON HER OVER. ENJOY IT. RELAX. If you spend your life sarging you will never enjoy those timeless moments of mutual love.
It won't last forever. Just accept that and enjoy it while it does. Just because it won't last forever DOESN'T MEAN it won't last for a very long time. You need to forget about the destination and enjoy the journey.
You don't go through life thinking "WHEN WILL I DIE OMGGGGG!"
Instead you enjoy life and take the challenges as they come.
So, stop gaming her, tell her you love her, express your immense attachment to her in the form of passion, but leave out the relationship shit you keep going on about. It is VERY unattractive to girls.
Just because she doesn't say that stuff doesn't mean she isn't into you. I was similar to you in my first relationship which lasted 21 months.
Start being alpha and dominant. I know the game never ends, but just relax and be you. That's the only choice you got. Keep doing what you do and you will cause your own demise.
Good luck buddy.