I am not going to my cousins wedding.

first of all I want to apologize if my writing is wrong because English is not my first language.

My cousin has been with his wife for 6 years for now and i have good relationship with them i would not call it friendship because we have generational gap that makes it hard.
So about the wedding they already had marriage registration but now they decided to do ceremony in church and invite everyone because they had really small ceremony years ago that i wasn’t invited to and i was really hurt by it but whatever it was in the past. They also decided to do baptism ceremony for their child along with wedding.
Now this is really big deal in our country especially in older generation and even tho i am not religious i respect their choices and I’m happy for them.

So problem is we found out about all of it 8 days before ceremony that’s when invitations where sent,
I was exited and I texted them thanks we will come.
Problem is we are unable to go now and my cousin and his wife are upset about(me and my husband)
To clarify we sad yes at first because we didn’t know that our house would sell in the same week. Our reasoning is purely from outside factors like we are trying to sell our house for a really long time for now and for some twist of fate it got sold on this week
And now we have very limited time to pack our whole house and move abroad yes we where planning this but execution was dependent on when and if our house would be sold so now we have to do everything very fast. We have only few days to clear out whole house get moving company and move abroad. If i knew that house was going to sell I wasn’t going to say yes to invitation. Another reason is that i thought it was relatively small ceremony but today i found out there will be 200 people invited, and so much people while i am pregnant puts my child in danger. Like if i get virus or flu it’s ER type of risk.
So today my mom called and we were telling all this to her and we told her we where not coming most likely, she told this to my cousin and his wife and the wife texted me angry demanding answers, i want to acknowledge that i am in the wrong for not calling them up today but we where in middle of so many things that i forgot.

I texted her and told her that we wanted but we couldn’t she was upset for not telling her earlier and was very passive aggressive, I understand her side and all i want is not to be in this situation what can i do to fix it.