OMG! They need to focus on getting into college. Do you have girls or boys?
Keep them active in team sports. My girls have friends that do not do any sports and their entire focus for developing their self esteem is heavily focused on their appearances and catching a boys attention.
I think its great if they have a boy and he is a friend, but being exclusive can lead to a major distraction. Most kids go off to college change at 18 when they get there and then change after graduation. What one thinks they want also evolves by the time they hit their mid 20's.
If a girl has any strong sense of their self esteem it is also partially because they have a great relationship with their dad. Dad's have a huge impact on their girls.
Most think it is the mom. Take a girl to buy a prom dress and chances are the girl will pick something less revealing if shopping with dad than mom.
I don't know if what i said helps. Stay close to your kids, becuase if there is a ever a broken heart during the teen years it is really painful, its hard to watch as your child gets dumped or just gets too involved before they really understand what it means.
Ask your teen what is the driving force for being exclusive? Sex? Then that is another whole can of worms. Good luck.