NAL. You need a lawyer. Plan everything down to the minutae. Have a backup plan, and a backup backup plan. Steel yourself. Steel yourself for the tiring battle ahead, long and weary mudslinging surely. It will be draining, mentally and physically but the casus belli is their doing, lay waste to them till the end.
I usually lurk but these days, I see news of men breaking often. The easiest way out is not the only way out. Be strong, if not for yourself, for your kids.