This is what I'm looking for also (new here - hi!). Ideally someone who is married (since I'm also married) and not interested in leaving their spouse. Really just a best (female) friend who I can also get physical with. I've come close to this before, but it didn't work out well because we weren't in the same life situations/needing the same things. I think that's key - being on the same page and equal footing so no one feels left behind.