I suggest you get a large piece of paper and begin listing likes and dislikes and advantages and disadvantages about each option in separate columns...
If you are minded you can give each items points and compare the totals but simply seeing everything written down is a good way to see the solution to a difficult problem more clearly...
The most important question is will you have any more practical support and companionship from friends and relatives in France?
Although being stuck in the USA it might seem things will be better elsewhere, the true fact is everyone in France you used to know has moved on and there is no gaps in their lives where you used to be - you could easily be just as lonely among friends and family!
When you have gathered and tabulated the data and tested the opinions of the children it will be time to talk to your husband.
If you make the move it will probably signal the end of your marriage but you give the impression it is doomed even if you stay...
If you have no plans to form new relationships and to provide your children with a father figure then moving would deprive them of the contact they do have, even though it is meagre, and they would be worse off...
I wouldn't be very surprised if forming new attachments or moving and forming new attachments would prompt a change in behaviour and attitude from your husband and extended legal wrangling is something you really do not need over the next few years.
If you move he will have more money than you...
I suggest such a difficult problem cannot be solved.
As money is not a problem I suggest you take your children on an extended vacation to France to visit your family and friends, explore a little and to give them a taste of the French way of life.
This will not only give you a chance to test whether moving there will be beneficial for you all and is likely to be good for your general state of mind and health, but might also help to concentrate your husband's mind...
If he can be persuaded to visit you during that time it will give you the oportunity to show him what his work addiction is costing him and that money isn't everything!
Good luck!