Or maybe the reality is that he isn't happier now and has to blame you for that too!
Big surprise (NOT!) I doubt he has figured out why he's not really as happy as he had expected to be following the D. The WAS rarely ever figures that out for themselves. Like idiots, they just continue taking the same wrong paths that have failed to live up to their expectations as before, hoping for a positive outcome. No self-introspection, no soul-searching or post-analysis of just what they did to mess up their own lives. No growth. Just repeats of the same mistakes.
And so when they continue to fail to be satisfied, even after they've jettisoned their M, they go back and blame the LBS for their predicament. That's what your ex is doing, Karen. Passing blame. Ignore him.
Will they ever figure it out? Who knows? It's not likely given their current mentality.
Just focus on what you can actually have an effect upon or control, dear friend. Let your ex be his own problem.