One-Time Entry Only
We love this life philosophy. If someone wants to leave you and stop being a part of your life, let them. However, if they try to come back, just send them back to where they came from. Easy as that. If someone is willing to leave, they must be willing never to enter again.
It's not true that she doesn't care; she just knows they will come back and try to enter again. However, it won't be possible anymore. Once you get out, you can never come back again. She respects herself enough, and she should!