Most men stop being sexually active around age 70 years old.
That means once the man reaches age 55 they are usually sexually active for another 15 years but that's not the case for all men.
I've heard of some men still being sexually active after age 70 and some even at 90 years old were still sexually active and interested in having sex.
Most people after age 70 who are sexually active usually use condoms for safe sex.
Your sex drive usually diminishes after age 70 but it's normal for some men to still be sexually active after that age.