As to specifics
If I am not the source of information, I don't share it, when the info is in regards to sexual details. As in, the details a partner shares with me, I don't share with others.
One of the things that I have a problem with in the places, sites, groups, and communities, both online, in real life, and the mix of both, is that it seems like offense is more the norm than respect. These are topics (love and relationships) are very emotional, so there are going to be heated discussions.
(It is not my intention to pick on people. In fact, being respectful and not offensive is something I need to work on. It really sucks when a person who was as big a part of this forum as Boring Guy gets banned. Often I was confrontational towards him, which means I was part of the problem.)
But anyway, in all the places that are known to be "open minded" in regards to sex, it's as as if there is an unspoken rule that you must have "thick skin" when it comes sexual matters, that there is no room for sensitive people, or as if humiliation by others can teach humility when you are talking about something like sex -- where each person has all authority in regards to themselves, and absolutely none except that which is freely given or willfully submitted to. Coercion is wrong; shaming is wrong; fucking with a person's mind is wrong; being disrespectful is wrong; violating another's autonomy or spaces that are sexual are wrong.
When I say wrong, I mean seriously wrong, as a person's emotional health and sexual health and being emotionally/sexually healthy is in many ways directly linked to spirituality. These are normally quite sensitive aspects of our lives emotionally. They are easily damaged, and when people exist in a place where their emotional sexual health is poor, it can take a life that would otherwise be perfect and turn it to shit.
It doesn't matter if you are mono or poly. If you have emotionally unhealthy sex life or sex partners, it is damn hard to be content with life.
As far as needing to know your partner's details, that is a sensitive issue. But I do strongly feel that the most intimate relationships are ones where all involved feel safe enough to fully share.
I don't have to be "involved" in my partners' relationships, but my preference is much closer to family style, or fully integrated partners, as opposed to separate. Mostly because issues of time are less of a problem as well as intimacy, as a true friend, a close friend -- even without any sexual aspect -- is in many ways just as fulfilling a relationship -- and in some ways, more fulfilling -- as it is the sharing of life that to me is priceless. Just one relationship like that is all I need, and I feel blessed to have it. It is often easier to find those relationships with those I am not sexually involved with, but the sex doesn't defile those relationships. It just seems like a rarer find.