What's it like? It's just life. You keep living, with or without kids.
What does bother me some is the moral high ground some people take when they know you don't have kids. "You couldn't possibly understand what it's like." "Once you have kids, you'll know." To some extent, that might be true, but I don't think it's impossible to make judgements about certain situations without being in that situation entirely.
Some people tend to make a lot more judgements about me and my decision not to have kids than I do about their choice to have kids. "But... no kids? That's so selfish of you!" Then 10 minutes later... "aren't you worried about who will take care of you when you're older?". WTH?