If you want to file on your own because you want to stand on your own two feet, then you should. If you want to file on your own because you are the kind of person who likes to get these things out of the way early and he is dragging his feet, then you should. If you want to file on your own because he is a sh!t dad and would only spend the money on himself (and not the kids) then you should.
But, if you are filing on your own as some sort of punitive punishment / revenge, then you shouldn't. If you are filing on your own, and the money he would have saved would have gone on your kids, then you shouldn't. If you are filing on your own because you think that this will make him realise he was better of with you, then you shoudn't.
and lastly ... if you file together because you are trying to 'nice' him back, then you should definitely file on your own.
One set of reasons are about it being better for you. The other is about it being worse for him.
But that's just my 2 cents. Others may disagree. You may disagree.