In summary, I personally think a direct and honest approach works great. You can further point out that you like to have your time open and without attachments without pointing any fingers at her but laying out how you like to plan your events and time. It puts things out there explaining that too much togetherness isn't something you strive for so the ball is squarely in the other person's court and you've kept it about you, not them (as you laid out in the first response)