Originally Posted by Indigomontoya
As for your jealousy, I just had to push past it, she is with you and will come back to you, so you have to realize this...even if TP goes and stays over at Mr. A's place she will eventually come back to me physically and emotionally (plus all her stuff is here)...stop comparing yourself to him as well, you each bring something special to your girl....as TP had to point out to me many times before it sank in.
That's not always the case though, often relationships are ended because they find someone that is more compatible with them. Because they have a connection with you they may first broach the subject of "the 3 of us can live together" but sometimes they do not.
I guess it all comes down to how much faith you have in your relationship, and if you're willing to accept a new person living with you. On the plus side I think having that kind of "pressure" would also make you a better partner in some ways because you can't just settle into a "rut" as easily.
My first gf and I have basically grown together over a decade now, so we have that history and similarities such that her finding someone to replace me (or vice versa) would be very unlikely. That said anything is possible, "open polyamory" removes the security blanket because you're free to keep looking for new partners.
Part of the reason many marriages end is because while they may not be openly looking for new people after enough time they will randomly meet someone more compatible and start questioning their relationship - "Why isn't Joe more like Steve?" . Open polyamory is like this except you are putting yourself into the game over and over again, increasing chances of finding someone "better". However polyamory at least gives you the option of being together in a group which is a lot better than the monogamous path - the end of the relationship.
Some people are of the opinion that the best point of being poly is finding new people that are interesting and possibly more compatible with you. So people like myself in closed relationships aren't getting the benefits they are. And that is true to some extent, however they usually fail to factor in the "time" needed to do all that. I'd rather be putting time into existing relationships that work, family and hobbies than be constantly on the hunt for new or better people. Sometimes settling down and concentrating on the bird(s) in hand is more productive, if that's your kettle of fish.