We all live together and sleep in the same bed. We do have the occasional threesome but mostly the sex is separate (me+MrS or me+Dude, the boys are straight). We have been navigating the co-habitating polywaters for a year at this point. Things have evolved over time. MrS and Dude were best friends before I ever met Dude - I know that they care for each other in their own right (not just through me) and would never want to hurt the other, which I think has led to their comfort seeing me physically interacting with the other.
At this time we have gotten to the point where the only boundary is that I won't have sex with either one of them if the other is in the same room but not involved. (For instance: if Dude and I wake up and want to get frisky but MrS is sleeping we will move to the couch.) Dude wouldn't mind (he has a voyeurism/exhibitionist streak) but MrS says he would feel uncomfortable.
Hand-holding, lap-sitting, boobie-fondling, kissing, cuddling, etc. all okay - sometimes the other will join in...or not - but these are things that I also feel comfortable doing in front of my closest friends. Dude's primary "love language" is physical affection and he needs a LOT of reassuring touches. MrS does not. Until quite recently I felt uncomfortable with this and tried to keep everything "even" - if I rubbed Dude's neck I would go rub MrS's, etc. This ended up with MrS feeling pested with physical attention that he did not want/need and Dude not getting enough touching - which triggers him to feel "needy". Once they got through to me that things didn't have to be "even" (the same) to be "fair" (everyone getting what they want/need) I got over my anxiety in that regard.
Now, I don't think that I would be comfortable right off the bat witnessing them being as physical with a brand-new girlfriend that I wasn't friends with yet...but I would expect to be working toward that if the idea was to include her in our co-habitating poly family (not necessarily in a relationship with more than one of us but a day-to-day full-on full-time cohabitating famly member). If she would want to have a "separate" relationship with either of them (i.e. everyone knows about everyone but metamours having only a cordial acquaintance level of involvement) that would also be fine but I would expect the PDA in my house to approximate what they would do in public (and would modify my PDA with both of them - the one she was involved with AND the other - accordingly).
Me: poly bi female, in an "open-but-not-looking" Vee-plus with -
MrS: hetero polyflexible male, live-in husband (21+ yrs)
Dude: hetero poly male, live-in boyfriend (3+ yrs) and MrS's best friend
Lotus: poly bi female, "it's complicated" relationships with Dude/JaneQ/MrS (1+ years)
TT: poly bi male, married to Lotus, FB with JaneQ
VV and MsJ: bi-women with male primaries, LTR LDR FWBs to JaneQ
My poly blogs here:
The Journey of JaneQSmythe
The Notebook of JaneQSmythe