npc sex duration setting - default   m1 visit another household m1 have sex with f1, invite f2 to watch   f2 watch, then masturbate later f2 spouse m2 join sex with f2   m1+f1 sex over. f2+m2 sex still ongoing   m1 then have sex with f3   m1+f3 sex over, f2 sex still going.   by the time m1 leaving, f2 sex never end