I've got two kids under 5. For now my husband and I trade off time taking care of the kids. My youngest still needs me at bedtime, so I don't leave the house until she's asleep, which still gives me a couple of hours to socialize. And every few weekends I take the kids out of the house for a few hours so he and his girlfriend (who also has kids) can have some time alone.
It works for us. And more importantly, it works for our kids.