I found this great article from a blogger who is popular often on Fetlife. He describes the point I was trying to make, way better than I can (and clearly, if this guy is writing about it, I can assume I am not the only one who has noticed this phenomenon. He is heavily involved in Poly and Fetish etc)
http://www.theferrett.com/ferrettworks/2012/07/all-women-and-never-men-a-rant-on-a-polyamory-i-dislike/
It's a fabulous article and I found myself nodding along.
I mean, I understand your points (I am a man, therefore I have the male parts already, so why would we need to bring another man into it) but I am willing to bet that this same logic would not be applied to the women. I imagine you have never said "Hunni, I really want us to bring a woman into our relationship, but only one. You don't need any more than one female experience because she has female parts and therefore why would you want to try another" Does that make sense?
I guess this is where the "female but no male" rules confuse me. I am not trying to be awkward or mean...heck this fantasy (as well as the male/male version) is part of my relationship and I am definitely not against it in any way. I also think that if your wife/gf genuinely ONLY wants to be with a woman, then that is totally cool and her choice. I think I am personally just trying to understand the logic of opening your relationship, but ruling out an entire sex when doing so? Yes, I do understand you have the male parts, but here is my logic:
Your woman is bisexual (I assume, since she is with you, a man and also interested in seeing women). So we can assume she is attracted to both sexes. Yet in this version of an open relationship, she has been allowed free reign to delve into as many female relationships as she wants (Understanding each one is a new and unique experience) but as far as the males...well she only needs one to be satisfied? Does this make sense?
I think you are over-simplifying to say a woman will bring something I haven't got and a man will bring the same thing I have. In fact, this statement seems to focus specifically and only on body parts. (which is kinda my point. Its the body parts that seem threatening) A woman (just like a man) can be good at certain acts, or bad at them. She could be rough or gentle, sub or dom...etc. As in...women bring as many complex differences as a man would. The only thing she literally cannot bring is a real flesh and blood penis. This is the only thing I can see would be different...her body.
I guess I don't believe that one sex is any more threatening than the other. If your lady is bisexual and you guys agreed on an open relationship, I guess I just can't understand the ruling out of one entire sex....other than seeing them as more of a threat.
The guy in the article above articulates this so much better than I can. However, like anything, I am willing to have my eyes opened if I am unconsciously being ignorant or overlooking something. Your points so far have definitely given me more of an insight into how you think. I am fascinated about this!
As for your last point: I don't know why men/men isn't just as common, but I for one wish it was! :D