There are different ways to have "Me time", I've got no interest in being out drinking all night, coming home in the early hours and feeling crap the next day, but I wasn't into all that before I had kids really!
I do need and enjoy "Me time" though, but in ways such as the following -
the odd weekend away, just me and dh. (We only do this around twice a year but it does us both good),
Meeting a friend or my mum for coffee or stopping off for coffee on my own sometimes!
The chance to read/listen to music uninterrupted,
I had a shopping day with my sister recently, and a day in London on my own, enjoyed both
Seeing a West End show,
Going to a country pub for a meal with one or two friends, (prefer small groups to huge crowds but that's just me)!
I enjoy all these things as much as others enjoy all-nighters, my SIL commented once that she found my choice of activities a bit boring and I should let my hair down more if I can get a babysitter, but all these things for me ARE a form of letting my hair down, depends on what type of person you are. Couldn't do a 10 day holiday without the kids though, my friend can't understand it as she does this a couple of times a year, but we're all different!