Just because no one practices magick doesn't mean that natural energy of thought and emotion doesn't create an effect. It's very possible that she has an emotional attachment to you (yes this acts like a magick bind/link) and you sense it and are compelled by it. Sometimes we cast away the people that care the most, so before deciding to magickally break this bond, consider your actions carefully. Usually such bonds/binds occur because at one point both people felt mutually "close" to one another.
To break the bond is just like breaking a bind. I recommend using a rope in ritual, tying something of yours on one end and hers on another (representing each of you). Name the rope itself the bond/bind, and then cut it or burn it in the center to break it.
Again, be sure this is what you really want. Once something like this is broken, it is very hard to get it back. You can't get it back through magick. There is no reverse to breaking away. It is a banishment of sorts, and it is permanent. You would need to begin again from the start just as you did when you first met.