Metamours are not children, and as a pivot partner you are not Halloween candy to divide up. Negotiating resource investments in relationships is not like deciding who gets how many Snickers bars and who is stuck with the malted milk balls. Three-way communication is useful to build trust and get a clear understanding of needs and capabilities, but ultimately the pivot partner is the master of her own decisions and resources. If someone isn’t getting what he needs from her, that’s something he needs to take up with her, his partner. And she needs to take responsibility.
