My GF started turning into a real bitch (no surprise). She was pretty much turning every little thing into a fight.

One day I had enough and told her it was over. She started crying (manipulating), I gave in and took her back. From that day on, I also showed a bit more beta traits than usual (started being more caring, apologizing when I was messing something up, and even let her spend more time around my place). The relationship improved significantly. No more fights, we still have sex whenever I want and she started being a lot more submissive and listens to anything I say. Why does beta game work? I'm confused.