I am separated for over a year in process of divorcing. What is the best way to file taxes.?

My wife and I make approximately the same money. Last year she landed a good job that pays her more money per year than what I make. We have two children. Will it be better for me to file married filing separately or married filing jointly. Since she received a substantial increase in wages I am thinking she will be on the hook for higher taxes. i do not know how many allowances she has claimed.