Advice

So through therapy I have been learning to stick up for myself I normally hate converttation however learning to set healthy boundaries. So I have these two bridesmaids who are my cousins. Let’s call them a, k Back story ( we were close growing up and drifted off as we got older. They are very judge mental and love drama and criticizing people. I have not picked out my party yet but It is Assumed that they would be bridesmaids. Okay so I get a call because my aunt their mother never received the save the date even though I mailed it out twice we mailed them out on April 23 and her std got lost. According to my cousins I am plotting against my aunt and not inviting her. so my cousins who are very rude said that they don’t want to be in the wedding party , they use that as a threat if I don’t do something they want . Last time they threatened it I was pregnant with my still born but because they struggle with infertility they threatened to not be in the wedding party, So I responded that was fine I’m sick of tip toeing around them and getting ridiculed about everything, now my mom is mad because I don’t want them in the wedding . I cut them out of the wedding and feel better that I stools up for myself but instant regret followed that I may have hurt their feelings