I think it depends on the age of the kids, the support network you have around you, how much spare cash you have and how busy you are with work.
So we have no family nearby, both work FT and so rarely go out as a couple because it's difficult to find babysitters and we are bloody busy the whole time. That's a bigger issue than going out with friends.
With friends I go out a few times a year but I'm nearly 50 and we were no longer at the 'go out dancing every weekend' stage even before we had kids. We are at the 12 people come to our house for Sunday lunch stage and spending every day at Sports Facilities watching the kids training and chatting to other parents stage. And since my friends are either workmates or other parents it means I see people regularly without having to go out clubbing.