After four years together, I recently got engaged to a wonderful man, and our wedding is scheduled for July 2016. We are planning a very small ceremony and reception, with a total of only 24 guests, mostly family. My fiance's SIL (soon to be my SIL I suppose) just announced that she is pregnant (with her first), within weeks of us announcing our engagement. She has a history of "stealing the show" when it comes to family affairs, and also of excluding my fiancé and I from family related events that she organizes [for example: she often has parties, and will invite my fiance's sister and parents, who live three hours away, well in advance, but does not invite us until literally the last possible minute, and we often have to work nights, which she knows, and then are unable to attend, etc. At her wedding, last summer, she had several bridesmaids, one of which was my fiance's sister, but I was not included in the bridal party, despite knowing her for many years. Onviously it's her prerogative who gets to be a bridesmaid at her wedding, but she then used it against me, saying that because I was neither in the wedding, nor actually part of the family (again, despite having been dating her then-fiance's brother for three years at that point), I was not allowed to attend the rehearsal dinner, or the pre-wedding "family only" brunch.]
It occurred to me, once she announced her pregnancy, that when our wedding happens, she will have a baby (judging by her due date it sounds like baby will be about 8/9 months old at the time of the wedding). I have been to a wedding before that was utterly ruined by babies screaming the entire time. No one else coming to the wedding has a child. I am not anti-children, but I'm acutely aware of the possibility of the baby not only "stealing the show", which future SIL seems to LOVE to do anyway, but also SIL being stubborn enough not to leave if the baby starts screaming in the middle of our vows, etc.
What hadn't occurred to me was that I might have a say in whether baby is allowed to attend the wedding. I just read through the "toddler at wedding" thread in the general parenting discussion section, and many posters said things like "are you sure it's okay with your SIL that the toddler attends the wedding..." And then I realized that maybe I have some say here. I know she'll be miffed, but it is my wedding, and she went so far as to exclude me from her rehearsal dinner and brunch, so I don't honestly feel that bad about it. Future SIL's parents, who are super active and also extremely excited about their first grandchild, live nearby and will not be attending the wedding, so I'm sure they could watch the baby.
So, can I tell SIL, as politely as possible, something like "I'm super excited to be an aunt, but we've planned a very small ceremony for adults only. We are thrilled to invite you and (fiance's brother) to our wedding, but hope you'll understand that we would prefer it if you left your little one at home so we can keep the focus on (fiancé) and I, just for our wedding." ?? Well, my wording is a bit clunky, but you get the idea. Can I ask that of her, or is such a request unreasonable?