I'm sorry to hear your wife is going through that issue with her friend. It's not fun and can be a tough realization. You begin to notice you're the one always reaching out and when you decide to scale back and make those reach-outs less frequent you begin to see how friendships have changed. It's wonderful you two have each other. I feel so bad for people who have no one. I'm lucky to have my wife, our son, and my family back in Ohio too, and my writing. The writing, in so many ways, is the best conduit because it allows me to connect with others—like you and the regular readers of my blogs and books.
I've never been one to have a huge circle of friends but always considered the small circle I have to be very important and valuable aspects of life. Life is just very different without that. These phases never last forever though, as you've eluded to. Hopefully your wife's friend will work through her stuff and the friendship can resume.
Yeah, I think the hardest part is knowing there isn't much I can do about it. I hope this is just a phase as well. I think we all go through different valleys in our life like this.