Sleeping in a trough

First of all, I would never again buy a mattress that isn't double sided since there is no way to ever reposition it to allow the trough to be corrected. I weigh about 140 and my husband weighs around 200. The indentations from where we sleep are so defined that it is like laying on a 2x4 if you actually lie in the middle of the bed. The warranty refers to "normal body impressions" but you would think that the "impressions" would go away after a period of non-use, but they don't. My husband is away from our home more than half of the time, but his side of the bed is just as bad as mine. We have to use a comforter as a bedspread because the indentations are so unsightly...even when the bed is newly made. It doesn't help that that mattress is so thick that I haven't even been able to find top sheets that are long enough to tuck in on the sides. I had my last <$500 mattress for 20 years. We probably won't keep this one more than another year or two. I would prefer to get rid of it immediately, but it was outrageously expensive.