I say go with your game, if you are confident that you can make a good game.
Usually, I don't tell people to quit university, but you hate the course, will probably have difficulty finding a job after you graduate, and will probably dislike the job if you find one, so it seems there is not much to choose university over what you truly want to do.
I don't know how to convince your fiance though.
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Drain and plane and grain and blain your brain, and then again,
Propane and butane out of the gas main, your blain shall sustain!