The first sentence of my first answer is a reflection of a married couple who are (were) close friends. They found out (3 years ago) they could never have children after trying for several years and, naturally, were devastated. Anyway, as time went on �the group� started to produce offspring themselves and hold subsequent parties/dinners etc as is par for the course. We always invited them and always they declined as it would be too upsetting for them to see all the children running around playing.
Whilst I sympathise, I have a child, as do many of my friends and there isn�t much we can do for them when these social occasions arise. But it has got to the point that we no longer really consider them for our parties and events as we are just leaving them to deal with their emotions. Effectively they are shutting themselves away from dealing with, what sadly will be, a lifelong and recurring situation. We have tried to help and have �no children� occasions etc., but even then feel that mentioning children is a subject to avoid. This isn�t good for them, nor us really as it hinders natural conversation and enjoyment. (People with children talk alot about their children) But effectively they have isolated themselves from anyone with kids, and their social circle, rather than make an attempts to come to terms with their situation. Their social circle is dwindling and eventually will be virtually non-existent.
You need to try to avoid falling into this cyclical trap, by getting over your emotions and let your friends be naturally conversant around you whilst remaining sensitive to your feelings.