Popping in with the odd vote.
The front and back look like two different outfits.
You look smoking hot and happy from the front. Perfect for the costume party. Just lovely.
In the back, I would agree with your partner about it being too low, but I think it is the cut, not all the skin.
The front has lines in all the right places. So why not the back?
The cut of the pants create a strong line across your hips and the curve of your waist is lost here. Imagine if the pants came up to the waist. I think your curves would be emphasized which is more in line with the look in front.
Having the back cut so low gives it very a different vibe from the front.
... in my eyes that is.
Something to consider.
