I am not turned on by two women going at it. It actually has the opposite effect on me. I avoid providers that are indicated as Bi. I understand this position really limits my choices, but I do get to decide what experience I am going to buy.

Does anyone else have this sort of aversion?

Just as it is for each of us.  

As may be obvious from my reviews, I enjoy dates with "really bi" ladies and in fact my faves all happen to be in that category. But I've had great times with non-bi ladies also.  

As they say, whatever floats your boat, as long as it's consensual.

While I haven't noticed any difference between straight and bi providers, I think I know where you are coming from. I have seen a couple of providers that have described themselves as "Swingers" and for some reason it seems to mess with my head.

I like watching 2 girls playing and according to some of my favorite girls only a few are really Bi.  The TER scoring rules allow a higher score for some menu items, really Bi is one of them, and listing as Bi is a common for a higher score is common. It also opens up some sessions that otherwise would not happen so it's called, Bi for Bucks, Buy Bi etc.  

Just see who you're comfortable with, it is you're dime.

I really enjoy watching gals who are into each other, but I can generally only afford to see one provider at a time.

Your preference is your preference, but I'd think if I were seeing two providers at once, we'd all have a better time if they were into each other.

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Pauper