You answered your own questions! Plus listen to her actions, if they matched what she said, which in this case they did, then believe it.
What happened? You became too available, too familiar, and not mysterious. You didnt mention how you were before but im guessing you were around her often but then this came and it was sort of the "breaking point."
How do you prevent it from happening again? You said and already did it! This isnt 100% fool proof but it will keep her hooked. You became busy during those days. You werent paying attention to her, not talking, and thus became mysterious again boosting her attraction. Simply do your own thing!
As for the cheating. I.. What? I honestly think she just lost attraction because you were always there. And it was proven because when you withdrew, she chased!
