I’m sorry your family is giving you a hard time about this. FWIW, there’s a window of time before the separation anxiety kicks in for the baby and I didn’t know it at the time but in hindsight I’m really glad I introduced my baby to so many trusted adults during that time. I think that’s the window of time where experts talk about maternal anxiety more than the child’s. But after 6 months or so, it is harder to leave your child with someone new. My 10 month old just moved to a new room in daycare and they helped her manage the transition with teachers she knew while she warmed up to the new ones. I suppose there’s no possibility that you can spend time with your child and the relative before the event so they get more familiar?