The stress of work has been weighing down on you a lot more recently, so you decided to get a membership at a nearby gym and start exercising regularly. It would be a good way to keep in shape and blow off some steam. The walkthrough they gave you there wasn't very helpful, but you spent a little bit of time on the treadmill before heading home.
Seems you had lost track of time though, and as soon as you walk in the door your wife is there waiting for you.