After my 2nd child was born have stayed a size 16, so i look pregnant again. how do i get rid of the fat?

No easy answer: Sorry but losing weight is really about diet and exercise, regardless of the cause. You do gain weight when pregnant from the baby, the amniotic fluid, water retention but also from a greater appetite. The basics should be effective but changing habits is always difficult whether getting back into shape or changing your eating patterns. It is about calories. Good luck, you can lose.