I would have to agree with the posters above. I am not someone who wants details on what a partner is doing with other people. I do not need sexual details. However, I do want to know if my partner starts seeing someone else, I like to know a little about them (name, how they met, if they have other partners - stuff like that), and eventually I would want to meet them. I also like to know when they are getting together just so I can figure out my schedule. And we always ask if we had fun when we go out with others. I like to know if he had fun (answer is usually yes!).
That's not a Don't Ask, Don't Tell policy. I know my partner sees other people. He knows I do. We've each met most of our other involvements. Whip and I have talked about this boundary (he would tell me details if I wanted so this boundary is definitely my request).
This might be ancient history for some but the term comes from the now overturned US policy of 'allowing' gay people to serve in the US military as long as they never admitted or indicated in any way that they were gay. In return, the US military was not supposed to ask or otherwise track down gay servicemembers. (In reality, they did ask and did investigations.) So gay soldiers could not talk about, show photos of, or indicate in any way about their same sex partners. When I think of a DADT relationship, it is this no discussion, no indication, no snooping that I think of. And that is horribly dysfunctional.
I consider my personal boundary to be one more about privacy, and staving off the comparison gremlins in my head. Whip is not responsible for those gremlims or for my handling them. But not hearing sexual details helps me to not compare myself to his other partners. It's not something I do often, and I am not particurarly envious or jealous in general. But if I get started down that path in my head, well, it can be hard to stop. I also suspect that as I get more comfortable, this boundary will ease and change.