Even when your child is three years old, he will still have fears about losing you. When he was younger, he worried about losing sight of you; now, he is fearful that you will not come back, that you will die while you are away from him, and that he will be deprived of you forever.
Again, a very good way to reassure your child is to go step by step through what is going to happen when you leave him. The more details you can give, and the more you can confirm the details, the better. What you might say is, “When Daddy comes home from work, we are both going to get ready to go visit Aunt Sarah. I will have a bath, Daddy will shave, and we’ll change our clothes. Then we’ll put you to bed and we’ll have our usual song, story, and game. Then Mommy will lie on your bed and cuddle you while we talk about your day and what you are going to do tomorrow. Mommy won’t leave you until you are fast asleep, and the next thing you will know is that it is morning and Mommy will be there.”