I've done this before. I strongly suggest that if you are going to shack up you need to start on neutral territory. This means you both move into a suitable place so there is even footing when it comes to divvying up the living space.
This will help ease on any feelings of animosity, superiority, ownership and resentment. It's also great for making all the financial responsibilities of the property transparent so there are no $$$ surprises. $$$ is usually the argument base for relationships not working out. I suggest you proceed with caution and a realistic sense of what this move implies.