If sperm falls and dries does that place become napaak?

Assalamu Alaykum Mufti ,
1) If a couple has intercourse or does something of the sexual manner
and the sperm went onto other things
and If it happened at someone elses house , do we have to inform them .. and can Ibaadat still be prayed on this place … like Qur’an recitation .. and Nafl Namaaz ?
Maaf for the nature of these questions , i realise should have been more careful but now this is worrying me !