Consent means someone agrees to a sexual interaction. Ideally, it comes in the form of a verbal “yes,” but as long as either party was free to say “no,” “stop,” or use a pre-chosen safe word at any point, that can still be considered consent. Being married is not considered consent.
When one party is unable to stop the activity before or after it starts (including being unconscious or too intoxicated to consent) or attempts to discontinue a sexual act they initially agreed to, but is ignored or forced to keep going, the other party may be charged with sexual assault.