I'm very sorry you're hurting. That would hurt me too, so I can understand your feelings.

What I wonder - is your circle of friends made up of all single people? And is the other woman who is being left out married too?

I have found that singles prefer to hang out with other singles, and married people with kids prefer to hang out with other couples with children or simply just other couples. I think mainly because singles can relate to other singles better. Kind of like "we're all in the singles boat together!" kind of thing. And married couples also have more in common with other married couples, especially when kids are involved.

I am just guessing here, but it's possible that's what's happening, if your group is mainly made up of singles.