Lost a friend because I didn't take sides when another friend didn't invite her daughter for her daughter's birthday party

Sorry guys the title is a bit confusing.

I was part of a group of 5 friends where 3 of them had kids and myself and another one didn't.

There was a bit of drama because Friend 1 got upset because friend 2 didn't invite her daughter to her daughter's bday party. I tried not to get involved, in fact this is one of the many reasons I don't have kids, because of petty stuff like that. Friend 1 never said anything to friend 2 about being upset and pushed away from both of us.

She's still friends with the other two, but on our side I see the friendship is gone. I eventually told friend 2 who is still my friend and she had no idea that she had pushed away because of this.

It even took me a while to realise she didnt want to be friends anymore because she was giving mixed signals for a while and I only realised she had approached me again because she needed me (she needed a reference for a job). I actually didn't want to believe that was the reason because I like her and I helped her a lot when she was going through difficult times.

Maybe she expected me to take her side and be loyal, but it had nothing to do with me really and I don't need to have an opinion on this cause I don't have kids! I was upset for a while, there were other things that happened but now I'm starting to get over it. I will not be around people who don't value my company.