All perfect praise be to Allaah, The Lord of the Worlds. I testify that there is none worthy of worship except Allaah, and that Muhammad is His slave and Messenger.
There is no specific distance which a husband should leave and should not exceed between him and his wife in public. In any case, the spouses should sit in a bashful manner when they are in the presence of people and they should avoid any thing that may violate modesty.
Their entire conduct in front of people should be based on this basis.
As regards one of the spouses putting his head on the shoulder of the other in front of relatives, then if this is a way of enjoying, then this should not be done, as this an act which shows lack of self-respect; for more benefit, please refer to Fatwa 91996.
However, if putting one’s head on the shoulder of the spouse is not for this purpose, then this depends on the customs. If this is not something usual in the customs of the country (where the spouses live), then this should not be done, but if this is customary, then this is permissible, but it is better to avoid it in public.
For more benefit, please refer to Fatwa 89041.
Allaah Knows best.