Wow Becky...you must work where I do!! I have the same situation at my work. There are about 30 people in my department and of the 30 I am one of the two only women that are married and the only woman with children. In this group there are only 3 of us that have kids (2 men and myself) so I can totally relate.
There are a few people older than me but most are around my age or a little younger and they have the same party mentality. I personally do not care what they do in their free time but is is really difficult when EVERY corporate event revolves around alcohol, happy hours, bars, etc. I get a few snide comments here and there in regards to how I am not into that scene and I have to hear people drone on and on about how kids are so not for them and marriage is a trap and then the conversation proceeds to their drunken weekend exravaganzas EVERY week. Deep down I think they have to knock family life to justify their lack thereof and their behavior.
What I get tired of is that no one can tolerate any of the topics I would like to discuss like my husband or kids. I will listen to some drunken driving story for 30 minutes and go to talk about my weekend and people will literally wrap up the conversation with an excuse and walk away. I have learned which few I can relate to the most and they have become my friends and everyone else just exists. I just go home and enjoy the comfort of it and the wonderfulness of my little family and feel like all is justified in my world.