The Chareidi way of life does not allow Torah violations such as mixed dancing, mixed swimming, women wearing pants & sleeveless tops, and married women with uncovered heads. Hillel, the Rambam, and Rav Moshe ZT”L did not allow these, either.
A husband and wife must act with modesty in front of Hashem, even when they are alone, because there are rules of the Torah that govern their behavior. They cannot do whatever they like.
ALL Jews, whether married or unmarried, must be aware that Hashem is watching their behavior, always.
“Shivisi Hashem L’Negdee Tamid – I keep Hashem before me, always.”