Why is it so hard to have mom friends??

I'm kinda just annoyed at this point. Every time I have a mom friend, which has been like 3 times 😂, everything is great for a few months and we have fun taking the kids places, brunch with the kids, cookouts. Then all the sudden they just stop talking to me. I'm not sure if I'm doing something wrong but I have social anxiety so I try really hard not to make other people upset with me or say hurtful things. They end up just ignoring me and I'm not the type to bother someone about hanging out so we never talk again. Anyone else have this happen?