We used the airbed for the first time last weekend for DW's good sized son. When he went to bed, it promptly collapsed in the middle. The tubular legs that form a two foot rectangle rocked back and allowed the middle of the bed to sag several inches. We ended up taking the air mattress off the bed and putting it on the floor. I couldn't see any way to keep this from happening. Should the top of the back of the couch be resting on the floor? It doesn't.