WIY, again I have to say that you are not being logical but totally illogical. Secrets come back to haunt you and bite you in the behind. If you are not upfront with your potential spouse someone else will dig up the dirt and it will come out sooner or later. This is a tremendous sakana for Shalom Bayis and may lead to divorce. I know this for a fact and I have seen this happen. No one likes to be tricked or lied to and in case you haven’t heard lies by omission are also lies. There are gentle ways of telling someone about one’s past without chasing them away. And if a potential spouse chooses not to know well then that is their choice and one they both choose and accept to live with. In that case there are no lies because all the information was offered and rejected.
There are two major past discretions that one would need to discuss. One as mentioned before is drug use and the other is promiscuity. Both of which can have effects in the future. Heavy drug use can damage the brain, can damage major organs as well as cause emotional issues in the future. In addition, once you recover from drug addiction you are considered a recovering addict for the rest of your life. There is also a possibility that your children will be predisposed to alcohol and drug abuse so that is something that you have to be very concerned and careful about, meaning staying away from all forms of substances. In order to do that one would need the support and cooperation of their spouse. Imagine having an alcohol free home without an explanation. I can’t see that happening.
As far as having other partners prior to marriage, aside from the HIV factor, there are other factors which can be experience versus innocence. And of course the emotional factors of comparing one partner to another.
Should a young woman find out that her husband had other women before her and she knew nothing about it, that may end her marriage on the spot. No matter how frum the young man was at the time of the discovery. No matter how eidel or fine he was at that time. He would be looked upon as a liar and a gazlan. He would no longer be seen as “eidel or fine” no matter how much he had changed. Not only would this destroy his marriage, but it can cause HIM to lose bitachon and go back down.
I am telling you WIY, your male attitude and perspective is a very foolish and dangerous one. I am giving you a female perspective and letting you know right now. That if you had anyone in your life that you advised to keep his past a secret and not find a way to gently tell his future spouse that there are things in his past he is not proud of, but he is very proud of the way he has overcome his past and has risen above it and turned his life around; then you are guiding him down a path to disaster. Any bochur that finds themselves in this position should speak to their own Rav and even ask for their assistance in discussing the issue with the young woman.
There is one thing that you said that is quite true. A young man that has to work himself back up from such a low madreigah to such a sweet and emesdik madreigah is someone to admire and not shun. i agree wholeheartedly as I am a champion for Kids-at-risk. And they do deserve every chance in the world to succeed and live a beautiful and fulfilling life. Hashem has picked out their basherts, and those who are truly their sole mates will understand and admire them for who they are and for the courage it took them to be completely honest and respectful of them. Because marriage is based on honesty, trust and mutual respect. Not on lies and secrecy.