I like TP's thinking also.
Out of kindness, I lean towards to quick meet at first. Just enough to say 'hi' and prove to her that you are 100% on the page and in the know about their exploration.
More than that, for someone never exposed to any thinking outside the 'old' model, can be pretty intimidating and even scare them away before they have a fair chance to get their feet wet.
But as we've said many times here, good poly relationships really do require a certain level of at least friendship between all parties to succeed.
After that initial "have fun" meeting, the responsibility now falls to your husband. Unless it just happens naturally (she might even initiate it), he must push for a longer, sit down-get to know each other meeting. Dinner somewhere. An outing together somewhere. And somewhere in there, some time for you and her to have some private 'girl time' to establish some real understanding - and hopefully - bond. It doesn't have to be sexual - not a requirement. But you have at LEAST one common interest and you both need to be on the page about how you are going to nurture that interest. HIM !
Not that hard really. Try to be considerate, but don't waver on the necessity !