A person who profits from your lack of boundaries will call your boundaries selfish.

Anyone who has been benefiting from your lack of limits will experience the arrival of limits as a loss, and will frequently describe that loss in moral terms. The accusation of selfishness is a reliable sign that something was being taken rather than given.

When you hear it, notice who is saying it. Someone who never needed anything from your unlimited availability rarely uses that word. Let the reaction be information about the arrangement rather than about your character.