Groom refuses to plan his wedding around stepsister's 'busy schedule,' 'mom went nuts.' AITA?

"AITA for not planning my wedding around my stepsister's busy schedule?"

My fiancée (26f) and I (29m) are planning our wedding and we set the date not too long ago. My mom reached out after learning the date and all panicked told me that my stepsister (27f) couldn't make it and I should call her up and check different dates to find when would work better.

I told her that wasn't happening and our date is the date we've chosen, if my stepsister can't make it then the world won't end. My mom was taken aback by my response. She asked me how I could say that. She told me a sibling or any immediate family member missing a wedding is a big deal.

For background info: My dad died when I was 6 and my brother was 5. When I was 8 our mom told us she had a boyfriend and when I was 10 she remarried. Her husband had my stepsister with his ex-wife and they shared custody. Our plans once mom remarried revolved around my stepsister.

Christmas every other year was celebrated at a different time because she was with her mom and not us. Family parties were missed if she wasn't around because mom was pissed at anyone in the extended family who didn't make sure my stepsister could be there.

She would tell my brother and me we should wait to do something for our stepsister to be there OR she insisted on it and refused to let us go without her. We resented it. And we did speak up but mom said immediate family needed to be there for Christmas, for example.

I told her she wasn't my immediate family so I didn't need to wait. Mom also resented the fact we weren't with her every other Christmas Eve because we'd be with our paternal family (court ordered time our grandparents won). She never made everything stop for us though. She'd just tell us we could choose to be with the family vs going with "other people" (meaning our family).

Over time it got worse with her saying "why did you see x movie without stepsister, why go to the arcade event weekend one and not wait for weekend too so she can join". It was insanity. It really did a lot of harm to our relationship with mom. Neither of us wanted or needed our stepsister included to enjoy it. Neither of us wanted to be forced to plan stuff around her. We had no choice.

That's not how things are anymore. Which mom was shocked I was putting my foot down so strongly about it. She mentioned the immediate family/sibling thing and I told her I have never once considered my stepsister my sibling or my immediate family and I will no longer plan things around her because her attendance is not essential to me.

My mom started freaking out on the phone and saying it would really hurt her stepdaughter and husband's feelings to hear this and how she wanted us all to be together for something as big as a wedding.

She told me she'd pay the difference for a different day and I said no. I told her my days of catering to my stepsister's schedule are over. Mom went nuts on the phone. I ended the call and I'm dodging her calls and texts now because she's mad. AITA?

Here's what top commenters had to say about this one:

charmer143 said:

NTA. You've made your position clear. You don't consider your stepsister as part of your immediate family. Her attendance is not essential to you. Ergo, you shouldn't change the date of your wedding to accommodate her. Your mother will just have to respect that. Otherwise, she'll just be admitting that her stepdaughter's feelings are more important than yours about, you know, your own wedding.

fiestafan73 said:

Your mom is yet another person who has tried to force a blended family only to have it blow up in her face. NTA.

krumpettrumpet said:

NTA but enquiring minds want to know, what’s so important that your step sister can’t reschedule?

pochoproud said:

NTA. The fact that your paternal family had to go to court to be able to see you and spend time with you says a lot about your mother's attitude. Maybe time to go no/low contact with mother, not just on the wedding, but on everything.

account_for_mepink said:

NTA I am so sorry. You hear about this so often when a parent remarries- they prioritize the new stepfamily at the expense of the bio family. Good for you for standing up for yourself.

Don’t be surprised if your mother does not come to your wedding. She would just talk about your stepsister the whole time anyway. Congratulations on your wedding and now you can start building your own family.

Make sure you venue, caterer, etc knows that you are the only person who can make any changes to your wedding planes. Your mom sounds like the type who might actually sabotage it.

Serious_Bat3904 said:

NTA this your wedding not your mother’s.

Sensitive_Doubt_2372 said:

NTA This is about your day. Your learn no date is good for her. Even when you think you might of found a date it never be good enough. However depends why she can not be there.