Leaving breastfed baby with the grandparents??

My husband and I are visiting family for the whole month because we live across the country. My husband and I want to go to the beach for a day to get some alone time just the two of us. Our baby is 2 months and breastfeeding. I pumped more than enough to last, but what are some things that could happen besides the obvious mommy worry. My mother says she left my brother for a few days for a retreat when he was 3 months and he only wanted a bottle from then on. You think that will happen with our baby? I would be so heartbroken 💔