An ounce of prevention is worth a pound of cure. If your children are raised in a home with honest, open, respectful communication between the parents, this will be your teen's idea of what normal family life is like. If your children grow up seeing domestic violence and hearing screaming and name-calling, this will be your teens' perception of a normal relationship, and that could be how they'll act toward their date or what they'll be willing to put up with. Teenagers raised with violence may have received messages that loving someone means hurting them, and that if you love someone, it's ok to control his or her life. But even teens raised in a stable, loving home can still be fooled by suave, initially charming dates. If your teens feel bad for how their dating partner was raised, they have to know that they can't fix the problem; the dating partner has to work with a therapist or other professional to learn how to deal with others with kindness and respect.
Talk to your teen about red flag behavior in dating partners, such as possessiveness, extreme jealousy, disrespectful behavior, and downright violence and sexual assault. Convey to your teens that they are special people and should not be forced or pressured into doing anything that makes them uncomfortable. Stress that no one deserves abuse, it shouldn't be ignored, and that it's likely to get worse over time. You can discuss with them signs of healthy relationships: respect, trust, honesty, good communication, and support, and how poor relationships are categorized by fear, lies, anger, insults, threats, and violence.
Ask your teen how he or she would counsel a friend who was in a similar situation. Be open to what your teen has to say, listen carefully, and offer ideas about where they can get further support and community resources, in addition to telling them that you'll always be there for them.