In our case I felt really disturbed when I noticed that the other overheard me having sex with one of them. Our bedrooms are right next to each other, it happens occasionally. But our routines are quite diverse, that's why normally my husband and I go go to bed at different times than my boyfriend and I. It works that way. I made sure that they weren't involved in the intimate part of the other relationship as far as possible. It doesn't work for me otherwise.
After some time the situation became more relaxed and I was able to leave for some alone time with one of them and actually tell the other, that we would be away a bit. Never explicitly "Gonna have some sex now, see you"; more like "We are going to watch some film/cuddle a bit, lay down some time" and so on. As I said, I am not comfortable involving an 'outsider' in my intimate relationships. And my other partner is listed as an outsider in these cases. And I was and am the one having the most problems with this special topic.
If everyone is comfortable with it, your plan sounds like a possible way to handle your situation. Wishing you luck
Hopefully it works out. And I promise, that however you are handling things in the long run, the more all of you got used to a three person living arrangement, the more you will relax around each other.
Facts: 30, female, bi, v-type relationship with Sward (husband, straight, mono) and Lin (boyfriend, straight, mono), poly-fi and co-primary.