I don't know, I have wide hips (am 12 on top and 14 bottom) and I know what you mean, but I find wrap dresses can really work for this shape.
But some don't! A cut across the middle can make my arse seen.huge
But I have been told big bums and wide hips are all the rage now 
So flaunt it, and give Kim K a run for her money 
DP have a free and easy return system, so.I might order, say, 6 dresses, and only keep 1 or 2.