Hi seasnail,yay,I finally have gotten around to writing.
For us (my husband polynerdist and I) it seems to have worked that we let each other know from the onset that we have been in touch with someone for the purpose of dating. If we meet up with them, then there is no catching up to do. If we click then there is no catching up to do. Everything was talked about from day one. Now I am looking for female company only, there has been no change to that rule (I say rule because I see boundaries as changeable and rules not so much), I just have three men to tell. The tersiary not so much, it can wait but definitely Nerdist and Mono.
When we made our boundaries clear to each other we didn't write them down and changed them a lot. We aren't the writing it down types I guess. Each boundary we come across is discussed at length with each other and sometimes the person that it involves and their partner. I think it is just good ethical practice, even for small stuff.
Perhaps the biggest thing for me has been to check in with my own boundaries. I made my own rules about dating when I started out. They completely fell through when I met Mono, but they were very helpful when I wasn't sure or just plain not interested in someone. I could then say, "well I have these rules for myself and this is what they are..."
My rules were, if we go beyond a second date then you have to at least talk to my husband on line first so you know he is real. If they wouldn't then that was it for me... it indicated that they were either used to cheating or would engage in that (whether that is true or not depended on the person and sometimes it was just fear... all discussable with them)..and I was only interested in being open. Then they would have to meet and then there was the chance of being more intimate....
You can of course decide for yourself what you own boundaries for yourself are... but those were mine.