Hi! I'll be glad to help you with this issue.
First, let me say I can imagine how distressing this situation must be for you. On the surface it seems like a small problem. But in reality I'm sure it is disrupting the family's functioning. This is not an uncommon problem at your daughter's age. This is an age where there are so many developmental leaps and surges happening that anxiety is very prevalent.
After a while, the soothing/comforting activity that was found becomes the "normal" for the child. Waiting it out is not a great idea because it will reinforce the behavior that you do NOT want to reinforce: needing you near or next to her in order to fall asleep.
Rather, you want to reward the positive behavior, sleeping and napping on her own. But you have to help her get to the positive behavior. So let me give you a good behavioral technique for accomplishing that.
Right now, every night or at least very often you have someone sleeping with her or she sleeps in your bed or you in hers; the same at nap time. Now I want you the next time this happens to have a blanket or a sweatshirt that the main comforting parent who she sleeps with wears. It needs to be not your favorite. You'll see why.
You (assuming it's you, but if not then your husband, or both of you) wear that sweatshirt or use that blanket each night for the next 4-6 nights. After that, when it's time to go to bed, you tell her how much you love her, how she's your precious one. You repeat it. You then tell her that it's not the time for you to be asleep right now, but that doesn't mean you don't love her. And you want her to know how close you are to her so here's the sweatshirt/blanket that you want her to have next to her that will comfort her and help her know that she's safe. That she's loved. You repeat this whole speech. Very childish language. Speak in sweet, childish ways about how this blanket or shirt is like your love for her and like how good everything is.
And you kiss the sweatshirt or blanket and you give it to her and hug her. Then you tell her how in the morning if she sleeps in his room with your blanket/sweatshirt, when she gets up there'll be a special breakfast for her. And then you do NOT give in. Again, you do NOT give in. You just repeat that the sweatshirt/blanket will help her know how much you love her and that she is safe and that you are all protected. Then when she succeeds that next day, you make her the breakfast AND you give her a special toy for having succeeded that you have ready and waiting in secret.
This is the behavioral program. You have just learned the basic technique of Cognitive Behavioral Therapy (CBT). You are rewarding the desired behavior and you are helping her with tools (blanket) for getting past the negative behavior. So make sure to not give in. This is how parents fail in the CBT techniques, by not following through long enough. So don't give up.
Okay, I wish you the very best!
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