Can a military man date a married woman?

There are no laws governing military marriage. Military members can marry whomever they want, including same-sex partners.

Does single mean not married or not in a relationship?

In common usage, the term single is often used to refer to someone who is not involved in any type of serious romantic relationship, including long-term dating, engagement, marriage, or someone who is single by choice.

What is unmarried woman called?

Historically, Miss has been the formal title for an unmarried woman. Mrs., on the other hand, refers to a married woman. Ms. is a little trickier: Its used by and for both unmarried and married women.