Is self-defense OK?
Avoidance of danger is your first moral responsibility. But when you find yourself in a dangerous situation you could not avoid, defending yourself is absolutely the most moral and ethical course of action. It is also the most effective!
Knowing your attacker does not change your right to self-defense, and it should not change your conviction that you are worth defending.
Traditionally women have been given a selection of options that are either impractical, ineffective ("Spray him in the eyes with hairspray", "Get a rape whistle"), or don't cover the whole spectrum of possibilities in which self-protection might be necessary. For example, advice such as "Don't go into dangerous areas at night, stay home" ignores the fact that a high percentage of rapes occur when the woman is in her home, and also ignores the fact that some women must work after dark!
This advice also ignores the fact that some women are being targeted for violence by assailants who will not be deterred by casual protective measures which would work against random crime or low levels of threat.
Where can a woman who wants to learn about self-protection go for information and advice? Not to the police, who are often bound by department policy not to even mention the higher levels of protection in their talks to the public. Where can she meet women who have experienced being sprayed with pepper spray, or hit with a stun gun, to learn the pros and cons of those methods of self protection? Where can she talk with women whose range of expertise includes practical defensive tactics or even firearms, and who deeply understand more than one method of self-protection?
"Fighting back" is not an effective option unless you are taught precisely how to fight back - where can you meet women (and men) who have had extensive training equivalent to that given to police, and who are certified to teach the same skills to other civilians?
The answer is: AWARE.