It doesn't matter, does it?
I'm 67, retired a year ago, and I've been sleeping with a girfriend of my wife's for the past 2 months. I've been married to this dear woman for 32 years. I take great pains to make sure she doesn't find out about me cheating on her because I still love her very dearly. But you only live once and at my age I know that I'll never get another chance to have sex with another woman. It's just plain fun. And as long as nobody gets hurt then it really doesn't matter. So that makes it all normal. Wouldn't you say?