Yes on both. Many people here go to clubs or parties to meet people who they do not know to engage in sex. They prefer the variety and anonymity of doing so.
Others prefer selecting their potential partners on websites or the like, then meeting them with no sexual expectations the first time to see if everything clicks. Your wife, at least at this point, seems to be in the latter category. She would be more comfortable and develop sexual excitement over a guy if she knows him first.
A third approach, which she may like, would be for her to identify a guy she knows who is not necessarily in the lifestyle, but she finds attractive already (that guy at the gym maybe) and see if he's interested. She flirts, he responds positively, you all get together for you to approve, and they do it. She may indeed be more receptive if you aren't, at least at first, around watching.
If you are comfortable with it, giving her explicit approval to have a partner on the side when it feels right for her may make it easier for her. I was raised in a strict religious home, but have concluded that all people are non-monogamous in our own ways. Finding that path brings tremendous joy.