Here's what I'm considering proposing:
We not discuss poly for 6 months.
At that 6 month mark, we will revisit the conversation, but not necessarily make any decisions.
In the mean time, I will request that I can have female friends and make sure that they are only friends.
I will ask her to read at least part of "more than two" during that six months. I will also ask if she has any requests or concerns.
Smalltown, I get you feel your freedom too restricted in your relationship now.
I suggest will suggest thinking about it in a slightly different way.
I'm sorry to say, but if I was your wife and didn't want to open - your plan feels pressuring to me. I'm tensing up when I read it.
Six months to develop close friendships, and then what? You ask for more? Nope. Tensing up. Defensive.
I think it would be good, to entertain the idea really without bias, if you could reassure your wife, that you are
never ever going to pressure her to actually opening up, if she's not into it. It's actually going to increase your chances of opening up some day, but that means getting comfortable with the possibility, that she really isn't into it, which is kind of paradoxical. However I think if you could reassure your wife that you're
really not pressuring her, she could read the book. However, asking her to "allow" female friends goes
against the intention of reassuring her. I would not be doing both at the same time - it's like asking her to embark on the journey before she's decided about the journey.
I think there are really two, or three different things here.
1) Having a "less restricted" model of monogamy. Getting to a place of not feeling shame or jealousy or fear towards having female friends. This may however include respecting monogamy, exercising self-control and cutting contact if you see yourself falling in love.
2) Getting comfortable with the other feeling what they feel, including sexual attraction and/or romantic feelings. Getting comfortable actually speaking about those with your wife, not having tabu topics. Not judging the other for having feelings. Having a freedom of expression and opinion - without actually acting on it.
3) Considering polyamory - actually allowing sexual contact.
Please think about this: Could you be comfortable with just having step 1, or 1 and 2? Do they already feel liberating enough to you? Given your background,
only one year since you gave up your religion, step 2 might take some time to achieve. This is work for both you and your wife. I don't think you are actually comfortable with you yourself experiencing attraction.
When I read your motivations, except for the "I don't want to fight sexual attraction" sentence, I thought a less restricted monogamy may be enough for you, if you decide it is.
I also think the sexual attraction thing could be actually helped by increasing the intimacy with your wife. I think you can learn to transfer some of your sexual feelings towards others to a more general level (they are
your! feelings after all! they have in fact little to do with the other person

) and live them with your wife.
Could this be the goal for you and your wife?
I think polyamory could come later. Like, five years later or something like that. Yes, I'm suggesting you should just give the idea up for the time being - just my opinion of course.
You've done an amazing journey work together with your wife to break out of religion. You're capable to do develop in the same direction, and that is
so great. But I think it would be jumping ahead of things to actually leap into polyamory. Keep up the self work you've been doing to shed old beliefs. Develop your open mindedness and your comfort with yourself. Then? When your actually comfortable with feelings, with sexuality, with building your own life as you please? When you are are both more ok with your own strengths and weaknesses, with being independent on each other? The gate will open to actually consider the practicalities of polyamory without defensiveness, or to divorce and seek your own way.
Am I being understandable?