It could just be that i'm emotional/hormonal or whatever but i feel like i just had an argument that was completely unnecessary. My SIL invitied us on a vacation to mexico THE WEEK OF MY DUE DATE (April 22nd) I'm like are you kidding me....um no i may be popping out a kid that week and quite frankly i'm surprised that your planning a vacation with this in mind. I know for some families it not as big of a deal, but my husband's family (meaning brothers and sister) have been there for every kid's birth. This is the brother my husband best gets along with, we go to all of their kids events and i'm not feeling the same love in return. When we brought it their attention the response was....you shouldn't be upset....should i be upset that you telling me when i can or can't go on vacation. wtf? you haven't visited your hometown in mexico for 10 years and now the sudden urgency to go the week of our due date? when you have all summer to go?? i'm feeling frustrated, why can't my kid be as important as yours were??
Re: Issues with in-laws, needing some positivity sent my way
Chances are you'll go early or, more likely, late, and they'll be around for it. And if not, that first week you probably will want to be alone to figure life out as your own new little family.
ETA: it's also much easier to have someone else's kids be super important to you before you have your own.
I understand your frustration but there isn't really anything you can do about it, it's their life and they can do what they want, so try not to let it stress you out and just take comfort in the fact that at least your husband will be here!
Edited: Spelling
On the one hand, I totally get the exasperated and frustrated feeling of double standards. My SIL and BIL have, in the past, been really terrible about expecting us all to show up to their big out of town trips and other activities. For years we went whether it was convenient or not just to show support or because they would get their feelings hurt.
However, now that we have a son and a home of our own and we have started planning different things that we invite family to attend, they don't show up b/c of various excuses. They haven't come to any family get togethers that we have hosted in well over a year - not even Thanksgiving (they simply didn't show) or DS's 1st and most recently his 2nd birthday party (I was really bummed about his 1st birthday, but by his 2nd I was over it).
On the other hand, people's lives are their own, and as PP's said, vacations can be hard to coordinate. The fact that they invited you is kind of a poetic way of saying they are not keeping track of your life the way you are keeping track of theirs, and that is hurtful. But just the fact that they are going to be out of town the week of your due date is not in itself terrible on their part.
Bottom line, I would take this as a message that you should focus on your family and allow them to focus on theirs. Don't feel like you need to go to every little thing they plan, they are simply not going to do the same for you.
Take it as a liberating thing, rather than an insult.
I get being hurt that your DH's entire family will likely be out of the country the week you are due. And it is a little odd that she invited you to go - it would have made more sense if she said "we planned this trip and normally we would love to have you guys there but I understand the timing is bad and you probably won't be able to make it."
But to look at it logically, most likely you wouldn't travel to Mexico on a big family trip within a month of delivering or for at least a month or two after having the baby, so it is not like this was the one week you couldn't go. And when I had DS, my IL's did not come into town until about two weeks later. And it worked out for the best - I would not have wanted them hanging around while I was in the hospital and immediately after. But they live out of town, so when they did visit they had to stay with us. It was nice that we did not have to deal with that immediatley after having the baby. And as others have pointed out, you may deliver early or late - not that many babies actually arrive on the exact EDD.
So it could all work out for the best. As others have said I would try to just let it go. my SIL drives me and my DH crazy in a lot of ways, so it is easy to let her get under our skin but we have learned to just let her be her and focus on our little family.