Sex with my second wife. WoW. In bed, on the dinning room table, in the shower, the hot tub, the bathroom counter. the couch, the recliner, etc. I was needless to say pleased that she enjoyed it so much and would initiate as often as not. So...you're asking what's the rest of the story. hmm...neither of us were exactly spring chickens. I had some back trouble about 5 years before we met but things were fine at this point.
Some of our sex positions were stressful to my back. Eventually, I had some serious muscle strain and aggravated the bulging discs that had been building up over the years leading to excruciating pain, sciatica, physical therapy, cortisone injections in my spine (epidural) and arthritis medication because it was the only pain killer that would do any good.
The rest of the story-part II
Lost weight, got in shape, got divorced (sadly the sex was the only good thing in the marriage), stayed in shape, work out regularly and have had no troubles for over 10 years now.