There is no 'us' to fight for, try to move on.
Dear Prudence,
My fiancé and I broke up a month ago after four years together because he changed his mind about having kids in the near future and wanted to be polyamorous with me and his new crush. I really do not want to be poly, and having kids in a few years (I’m 28 now, he is 30) is really important to me. But I feel regret and wonder if I should get back together with him and if this is just a big struggle we have to overcome. He is dating his crush already, and she is poly. Since he met her, he is convinced that being poly is the thing that will make him happy. Should I try to fight for us? I’ve been trying to change his mind for a month. Our relationship was great on so many levels. We considered each other soulmates, and he told me I’m the love of his life when he proposed to me in Paris one and a half years ago. Or should I try to move on? If yes, how?
— Polyamory Stole My Fiancé
Re: There is no 'us' to fight for, try to move on.
I do not have the capacity to be poly or to not want kids. Both would be deal breakers for me.
It's understandable to be sad and to grieve what you no longer have but it also should not mean sacrificing what you want at your core for a person who does not share the same thing.
He possibly doesn't want children anymore. He wants a polyamorous lifestyle. And he CHEATED on her! The first two qualities are fine, though sad when couples can't agree on them. But the last one is not. Do not throw away their boundaries and any more time away on this loser.
He can give the LW some flimsy excuse that the current g/f was just his crush before their break-up. I guarantee you the current g/f is who he was having an affair with and now he can bring it out in the open. The LW is too hurt right now to see the reality. But he cheated on her and threw their 4-year relationship away for another woman.
I know LW probably doesn't feel like it, but they have to propel themselves to literally get out of the house and just live. Meet friends for coffee, dinner, a walk in the park, etc. If they can get out of dodge, even just for a long weekend, that would be even better. Also, if there are hobbies LW enjoys, especially ones they may have let fall by the wayside, get back into them. And if there's a TV show their partner hated to watch and they'd turn if off when he entered the room, turn that shit on and blast it.
Don't try to get back together with him. Have your grieving time, stop communicating with him in any way, and move on.