Something like an STD should obviously be 'public knowledge', some don't. My friend recently dumped a girl three weeks before their wedding. He dropped the idea because he found out she had slept with "around 50 men" and had at one time been in a gangbang. The humorous part of this is my friend's ex-fiancee is an expressed feminist and was seriously pissed that he had even asked. She lied to him about it first, then later broke down and admitted it.
I come down on the side that if you're going to tie the knot with someone, it is their right to know about your past. That includes a person's sexual history, past relationships and so on. I'd like to think it's a reasonable expectation to know if someone you're marrying has slept with your friends or family, for instance. Healthy adult relationships, especially marriages, shouldn't have those kinds of secrets. Decisions have consequences, and a person's past is a good indicator of what they will do in the future.
I come down on the side that if you're going to tie the knot with someone, it is their right to know about your past. That includes a person's sexual history, past relationships and so on. I'd like to think it's a reasonable expectation to know if someone you're marrying has slept with your friends or family, for instance. Healthy adult relationships, especially marriages, shouldn't have those kinds of secrets. Decisions have consequences, and a person's past is a good indicator of what they will do in the future.