Well sometime a couple does not have the option as to wether or not they have sex. I am usually very quiet in be but my partner on the occasion can get loud. At the moment we live in a 2 bedroom unit with his son and our daughter., because of lack of room our daughter hs her cot in our room we are unable to have sex in the bedroom because she will wake up as she is a very light sleeper ( she wakes up when we walk around the room ) and anywhere else we run the risk of my partners son waking up.
so sometimes you really don't have a option.