This is a comedy about a group of friends who all live different lives. The beginning of the movie shows two couples. Alex and Leslie are very relaxed in their relationship. Then you have Missy and Ben who are sex crazed. Both couples are friends with Julie and Jason. None of these people have children. Flash forward four years. Both couples now have children and their marriages are suffering from it. Julie and Jason are still best friends having no problems. After Jason's birthday party, Julie and Jason talk about how it would be easier to have a child with someone and then meet the person you want to be with. They both agree to have a child together (to their friends' dismay).
When baby Joe comes, Jason and Julie adjust quite nicely. Their friends are in shock over how easy it is for them. Jason starts dating Mary Jane, while Julie begins dating Kurt. Mary Jane is wild and free and doesn't want children. Kurt has his own children and doesn't want to introduce them to Julie until he feels they are serious.
The couples all take a skiing trip to Vermont. There, they have an uncomfortable conversation about relationships and it is quite obvious that Ben and Missy are having problems. After Vermont, they divorce.
Julie invites Jason to her birthday dinner. He is surprised that he is the only one there. Julie admits that she is in love with him and thinks of him and Joe as her family. Jason tells her that he only sees her as a friend and that Mary Jane has agreed to move with him.
Julie is heartbroken and decides to move out of the apartment building that Jason also lives in. Jason and Mary Jane end up breaking up over her not wanting children.
Months later, Jason invites Julie inside his apartment. He confides that he is in love with her and always has been. They kiss and end up in bed.