From the concerned letter-writer...
From Shore's response...
The first thing I'd recommend is to read this interview, which I did with a woman in a polyamorous (meaning more than two people) relationship: 1 Man, 2 Women in a Polyamorous Relationship. I can't imagine you not finding it helpful.Like I said, follow the links.
I don't understand why you and your husband are so against meeting the other woman. What do you have to lose? Meeting her means having a lot more information about what your sister's getting involved in. How could that be bad? At any rate, by refusing to meet her you pretty much forfeit your right to have an opinion about your sister's relationship with her. You wouldn't care what someone who's never met him thinks about your husband -- much less your relationship to him -- would you?Yes!
Here's the thing: Your sister is either going through a phase that will pass, or she's really in love with these two people, and they really love her, and the three of them are going to live happily ever after. Either way, your job remains the same: to love and support your sister.
There are other possibilities. Even if this relationship doesn't last, her sister might continue to live as a polyamorous woman.
Bottom line: You can, and should, share with your sister your concerns, thoughts, fears, prejudices -- all of it. You get to talk about you. But you don't get to talk about her: you don't get to tell her who she is, or who she should be. You can share with her, for instance, that you genuinely can't understand how a person can love two people in the way that most people love one. But you can't say that no one can love two people in the way most people love one. The former is about you, which is fine. The latter is about her and everyone else, which is beyond your rightful purview.
Want to have a good relationship with your parent, sibling, or child? BE THERE for them when they come out or have a person or people they want you to meet.