Came home to my wife and son in the shower together

Like the title says... I was away on what was supposed to be an extra long work day. I finished a client dinner and hit the gym and then came home 2 hours early so around 7:30 at night. Walked in and house was quiet so I went upstairs and heard the shower going. Peeked in expecting my wife and saw her in with my son. They seemed to be really into soaping each other up so I stayed completely silent and just watched and then snuck back down stairs.