We are almost of the same age. I work out 5 times a week, 1.5 hours each, spending a little more time on strength than on cardio. There is nothing wrong with working out every day, as long as you do split routines. Muscle needs time to recover. The hypertrophy magic happens BETWEEN training sessions. At our age, the recovery takes a bit longer than when we were 20 years younger. Though I find that having the weekend off (or any other day or 2 days) is something the body appreciates, too. And no, you won't lose any muscle during that rest period