When we go to sleep then our subconscious mind starts working. Usually, people are extremely honest and cannot fake their body language while sleeping. It is possible to define what goes on in a relationship depending upon you and your partner sleeping position.
If the partners sleep on the opposite sides of the bed then it means that they need space in the relationship. If they sleep in this position occasionally then they need a good night's sleep.
If the partners sleep in this position then they have different needs from this relationship. One of the partner needs more intimacy whereas the other partner lacks space.
On his Shoulder
If the women sleeps on her partner's shoulder then it indicates that she likes to depend on her partner. It is necessary to live without him and become more independent.
Face to Face
This position is called as pillow talk as the partners have good conversation and contact between them.