My brother and my SIL recently had a baby. The baby will be 2 months on the day of the wedding. Both my brother and my SIL are in the wedding party, and my mom and I figured we would get a sitter to assist during the day and watch the baby during the ceremony. The ceremony and reception are both at our venue, and we have a house we're getting ready in. We even designated a room for the baby to be set up so he would be comfortable and it wouldn't be complicated with everything else going on that day. We are now less than 4 weeks away from the wedding and my SIL says she doesn't want a sitter, she would like someone in the family to hold the baby during the ceremony. I am not OK with this as I want to make sure if the baby gets fussy, whoever is holding him can walk away, so it needs to be someone who is not invested in watching me get married. I suggested inviting someone from her family, but she's still upset at me. Any suggestion would be helpful at this juncture.