Sexual abuse by definition is unwanted sexual behavior by a person upon someone else.
Sexual abuse can be a lot of things that aren't necessarliy unwanted sexual intercourse. For example: Unwanted touching or kissing, refusal to a condom or birth control, unwanted sexual behavior, etc.
And can also happen to someone at any age, whether 16, 31, or 53.
The biggest misconception about sexual abuse is that most people believe that it only happens to women, and never to men. This is completely false.
In fact, 1 in 6 males will experience sexual abuse in their lifetime
Another misconception is that it happens mostly between family, for example between husband and wife. While this does occur it happens the most by a complete stranger who sees someone as vulnerable to an attack.