MIL is planning a suprise party for her husbands 70th (he is an awful man, and a bully that I avoid as much as possible). She lives in another country and was booking flights for a bunch of people who had said yes to attending. She booked flights for me, my husband, my son (2) and my unborn child (F due Feb) too. Neither me nor my husband said that we wanted to attend. The last time we saw her we had said that we did not want to visit her this summer for a variety of reason, but that she is always welcome here to see our 2 and her other 2 grandchildren that live less than an hours drive away). By the way she has only met my son three times in his whole life. Anyway my husband has now decided that he wants to go because there will be people there that he hasn't seen for years (these people live in driving distance to our home by the way). I have zero desire to travel with a 4 month old (whose temprement we do not even know yet, what with her not being born and all) and a 2.5 year old for the sake of what I can only envision being an exhausting and stressful weekend away. It will require us sharing a living space with other guests, arranging and funding our own way home, finding/funding a dog sitter. We are already financially struggling to make ends meet which will not be easier when I am on maternity leave. I feel really angry and frustrated right now that she has backed me into a corner. Am I being ungrateful here or is she out of line?

EDIT: Thank you everyone for taking the time to reply to my post. I really appreciate you time, effort and various perspectives.

For clarification the flight is between 2 EU countries so passenger info isn't required at booking (though I did think at least a name was required - she does not yet know the name of our child).

The reason for the one way flight was so that we could choose a return time, and date that suits us best (aren't we lucky to have such freedom to choose...). My husband did not get confirmation, but is fairly sure that MIL would cover those costs too.

I intend to call MIL tomorrow and tell her that I will definitely not be attending, and therefore neither will the baby. My husband can choose to go with, or without our toddler, or stay home with us, but that is between them.

I hope that I can stand my ground enough to say that it was unacceptable and that I expect this to never happen again in the future, but lets see. One step at a time eh?!

Thanks again folks. I feel so much better for sharing this problem and getting such helpful and constructive feedback. Too bad the post was locked. I was not aware this would be a possibility (I am not new to bonkers MIL, but I am new here).