If friends and couples sleep in your house, it may have some influence on your family atmosphere. First of all, your family may feel uncomfortable, because they may be worried about whether your relationship will be affected. Secondly, your friends may feel uncomfortable because they are not familiar with your family environment. Finally, your friends and couples may also affect your family feng shui, for example, they may bring home the bad smell outside, or their married life will affect your family luck.
Therefore, if friends and couples want to sleep in your home, I suggest you communicate well in advance to avoid unnecessary embarrassment and influence. You can explain your family situation and geomantic concept to them, and you can also make some suggestions, such as letting them sleep alone or informing you in advance, so that you can get ready. In a word, maintaining good communication and mutual respect is the key to avoid influence.