I get a different impression from the post. Rather than quitting and marriage solving the problem immediately, I think she still has anxiety, because he wrote: "She still has anxiety, and I imagine she always will. But we are able to deal with this in a much more productive way. Sure, there are times where it all gets a bit too much"
I don't think it's correct to say "None of the therapy stuff did them any good" because therapy isn't mentioned in the post. If you meant counseling, he mentioned that positively, in the context of the useful decision to quit the job: "we found a private counsellor who could help get to the route of what was causing some of this anxiety — we then discussed a lot of these sessions and reflected on them and tried to put into practice some of the advice we were receiving. We also made big and brave decisions like my wife quitting her exhausting job up in London"