It changed our relationship, as skoorbaby has become the centre of our home life. Only recently have we come up with the idea of a babysitter, so that we can go out. Of course that's expensive, but we'll be doing it more often.
Of course we're glad we had skoorbaby (parents have to say that, but it is true!). My free time has been annialated. I define free time as time I have to myself to do whatever I want, like watch tv or play a video game without being distracted. Last week it was about two hours, tops (generally on the weekend, in the morning, before everybody else wakes up. Doing late at night works too, but I work out too early for that). I know a guy with three kids who finds a couple of hours a night for video games, but that's at the cost of ignoring his kids, which is totally deplorable to me. Skoorbaby slept a lot originally, so my free time was not so affected, but with her sleeping less during the day, she now needs constant supervision/attention!
Socially it's not changed all that much, since we bring her out. We've been to one movie since last summer (got a baby sitter), so going to movies basically won't happen. You will not be going to bars with a baby, either. We have had zero problems taking her to friends' houses or out to dinner or anywhere else. I knew a guy who said that in India (maybe just in his town) newborns are kept inside for three months to protect from the environment. That's garbage. We had skoorbaby out of the house doing chores when she was 5 days old. Starting her off early has made her easily manageable in different environments with different people.
So you can do things, but they have to be kid compatible. The nightlife is not.
You can do what HappyPuppy is talking about, which a lot of parents do. If you're like the father I mentioned above, you can even buy a nintendo for your 5 year old son and put him in front of it for _hours and hours on end_. Of course, his social development will be stunted and he'll be unable to properly deal with kids his own age (as this one cannot).
For me, to dwell on the negatives, three things come to mind:
1) Money. Skoorbaby costs us well over $1200/month take-home money.
2) Relaxation is not predictable. You can't go home after work and sit in front of the tv for a while, or go to bed when you want, or do other things without the constant possibility of it being broken up by a baby. Only recently have we had the chance of getting a full night's sleep without it being broken up by crying.
3) Every time you hear about something crappy in the world that somebody did to somebody else you fear about if it could happen to your child.
We knew it all going in, and so realize that you will lose your time that you currently take for granted. When was the last time we sat at home and watched a movie through, without it being broken in the middle? Well, back before skoorbaby was born. Pause button is your friend.