I've spoken about the issues my FI and I have had with the guest list before, since he wanted a large wedding and I did not, mostly due to my anxiety disorder, but also because we didn't have the money to pay for all of the people FI wanted. It was "ended" the last time with FI's parents offering us money towards the reception costs so that FI could invite everyone he would like.
I have been having anxiety attacks thinking about how large this wedding has become - it went from a simple 100 people to almost 250 people, and we're spending way more money than we planned. When FI was down over the weekend and we tried to order invitations, this became as issue. He was upset that I hadn't said anything before, and asked what we could do so that the attacks would stop. We agreed to bring the number of guests back down to 100 people, and to give each set of parents a number of people they could invite.
FMIL is in England visiting a friend and won't be back until the 18th. FFIL is fine with having the set number - he's happy to not have to chip in the money for the reception - but told FI he can expect to hear his mother "complain" and that I should expect at least one phone call about us "deceiving" her, since she did offer money so that FI could invite the extra 150 people he originally wanted.
Neither of my FILs have spent any money on the reception yet, and we have not sent save the dates to anyone, either (we'll be sending them to out of town guests). Are FI and I wrong for bringing the number back down, to save my sanity and some money? If we aren't, how am I going to handle with phone call without saying, "talk to your son" and hanging up? While I firmly believe it's an issue FI should handle, since it is his mother, she doesn't have the same set of boundaries and I don't want to be rude.