Somewhere I recall an article that said once a couple had scriptually divorced they could not go back together again.
So if this is true then husband #1 would have no claim on the ex-wife especially since she had moved on.
Besides if the woman wanted to get away from him bad enough to go through one of those JC committee sessions to get the divorce in the first place why on earth would she want to go back to him after being with the second husband who treats her well