How much personal life can you have while the military?

As much of a personal life as you can squeeze in once you leave the office at 1630 until you come back at 0730, as well as all weekend. Minus time spent on some exercises, TDYs, and deployments.
Assuming you are talking about an officer with a CE degree, you are going to be sitting in a office most of the time overseeing projects and managing programs.

I had plenty of personal life in the Military.......but of course not Always the freedom to enjoy it while on deployments.

It's not prison

The large majority of folks (with more than 4 years of service) are married and have famalies

far too vague a question. at one duty station you could be working bankers hours, and at the next, 12 hours on 12 hours off.

to my husband, ( Navy Officer) a Half day meant 12-14 hours actually working, not counting getting early enough to do some PT.

its just a job, and like any other job, when your off work, you can do whatever you want