Are bystanders typical in your bedroom? As a part of society I’ve never once been harmed by anyone’s sexual intercourse, even folks who invite bystanders. I think only societies that take great interest in conformity to some norm to the extent they feel the need to be angry about someone else’s nonconformity reap harm from private thought and activity. In that case I think the harm starts with society and ends with the individual rather than the individual harming society.