I used to love spinning classes, and have to admit to being hooked on them a few years ago attending several classes per week. I had an enthusiastic instructor,it can be hard work and if your not used to excercise it would come as a shock..You are on stationary bikes and you pedal to music, you increase the resistance with a dial as the instructor calls out instructions,you can slacken it off to make it easier to pedal, in theory you can pedal as hard or as easily that you like,my experience during the couple of years I did it,was that the people who don,t excercise hated this class. Why not try one class to see how you both like it, or if you both swim that would be a good option.