Are you a sister or a wife?

At the end of Series two of Big Love, Barb outs Margene as a polygamist after Margie was getting herself mixed up in a whole web of secrets and lies with her new BFF (best female friend, to those not in the know) and neighbour Pam. Barb, clearly nervous as hell says 'We are all one family. Margie is my wife....Sisterwife' Barb corrects herself (I am paraphrasing and I am not certain if this is totally correct).

As any ful kno 'Sisterwives is a term used amongst Mormon Fundamentalists to describe the woman who is also married to your husband.  It describes not your biological relationship but signifies that your relationship should be sisterly, using the Matriarchs Rachel and Leah as a spiritual template.

Ok, I am going to come out of the coffin and say that this doesn't sound a great deal all that fun to me, why?  Because my sister and I don't really get along, I think the idea of living with her would be hellish. However, being the sisterwife to a BFF would appeal and it is quite nice to know there is a term that would 'elevate' our designation from 'friend' to 'family' Sisterwife does that and since the success of Big Love and TLCs Sisterwives, I think that it is more in the public consciousness about what this term means.
But that is by the by, the point I am making is, by virtue of its biological associations a 'Sisterwife' is a woman married to your husband, married into your family but not necessarily married to the wife.

A lot of women seem enamoured by the Sisterwife ideal , a best friend who you share your life with, who looks after your kids, who you lean on and she you. We  place this ideal on high and pity the poor women who don't get a choice who their husbands marry, who have to live with  a woman who has different tastes, who isn't a BFF, who *shock horror* might actually prefer to spend time on her own and not with the first wife and we wonder then...what was in it for the first wife?  She has 'lost' something but gained nothing.

 I am concerned with the fact that I have seen a lot of adverts recently for a Sisterwife I can have sex with different wording usually, but the same idea.

People have to stop and think of what they really want.  It is one or the other. These women can not inhabit the same body and I will tell you why.

Do you want to live a poly life because you are bisexual?  Then so, you might want to think about dating women, getting to know and have a relationship with women and see where that takes you, you might end up with a very loving and supportive secondary who would be a good friend to your husband. 
She could be a lesbian? Or married herself?  Or just simply not have the time for a full time partner. The point is, she is the mistress of her own destiny and your husband might not be a part of that. Or perhaps you want a primary relationship with her and she you, it might be your husband who gains a Sisterwife, would that work in your family?

Do you want a Poly life because you want a Sisterwife?  You want a woman involved with your day to day life, you would like more children in the home and a friend always on hand to help when you need it? You want a friend who never has to leave at the end of the day.
She might be heterosexual and have no desire for you, she might abhor the idea, can you deal with having a woman in your life that you might have those unrequited feelings for? 

Expecting a woman to come into your home with the understanding that she must love and be sexually attracted to you both and the relationship to develop at the same rate, in the same way, is unrealistic, she might  feel one way at first and her feelings might change, how would you feel if she decides she doesn't want a sexual relationship to either one or the other of you after a point when you feel committed, would this be a deal breaker?  

Asking someone to relate to you as a lover at night and a sisterwife in the day is messy and confusing, she might feel patronised on one hand or used on the other. This would be especially apparent if there is a age gap between you. Who wants to try to switch their mindset from little sister to sexual partner?

Think of the social impact of introducing the newcomer in 'friendly' company, 'This is my partner' conveys a message, this message tells people exactly the type of relationship you have, it says, this person is someone whom I love, they are my equal and I feel this relationship should be afforded the same respect and stature of my marital relationship. 

'This is my Sisterwife' is a lot less easy to define, even people who know you might not know how to relate to her, perhaps she would feel hurt that her relationship to you being unequal and secondary to your relationship to your husband who has to be the primary focus for you both.  It puts an unpleasant homophobic slant to things, as if you need this pretense to feel that your relationship is acceptable, would she feel like the dirty little secret?

Does using the structure and terminology of Polygamy/Plural marriage offer up a crutch for you to hide behind and avoid using terminology more appropriate to your relationship?
Or perhaps you would feel that your relationship would be more correct if it follows a traditional and religious structure so you don't have to face your own sexuality and feel like 'other'?

These are all things you have to come to peace with before you consider opening your marriage.
So ask yourself, What do YOU really want?