I read an essay online last week that bemoaned the trend of being more Chareidi than the Chareidim. Essentially, the author went on to talk about how we went from separate seating in shul to separate "everything."
I wonder if she shares my views on why this is a root cause of many of the evils found in today's frum community.
I can't possibly address all the psychological issues of the innate desire of that which is forbidden, but I think it's rather obvious. One way the frum community can address the issue of pre-marital promiscuity and extra marital affairs is to address the general issue of sex in a somewhat more responsible manner.
But that begins at a very early age. If you wait until your child reaches the age of sexual ability, it's too late.
Children must be taught early on that there is nothing "wrong" with playing with those of the opposite sex. If boys and girls are friends, no ill will come of it. If they play board games, or hide 'n seek in an appropriate manner, they will develop into healthy young adults with healthy appreciation for the opposite sex.