It is common for babies to develop a strong preference for being put to sleep by their primary caregiver. To help your baby adjust to others, try having your partner or caregiver take over other comforting routines first, such as massage, bath time, or playtime. Once the baby is comfortable with them in those settings, have the caregiver gradually assist with sleep routines, perhaps by offering comfort or holding the baby until they fall asleep. Persistence is key, and it may take time for the baby to feel as secure with others as they do with you.