I've found as my kids get older my social circle what widened - once they're at school you have the opportunity to participate in school related events (evening ones, without kids) and its a great way to meet more people in a similar situation. I had a very enjoyable (albeit quite drunken) night out with other Mums from my 2nd child's class last night. Also, as they get older, it gets easier to be able to return to things you did pre-kids. I love being able to play in orchestras where there's a range of ages, and music is the thing we have in common, not children.