I take, from reading your reply, that you are both poly. You see others as well as him seeing others.
That is where I am different. I am mono, though he thinks I am poly, just haven't realized it. If I were poly, I wouldn't be so upset at this entire situation.
He has stated what he sees in me and that I have his mind, heart and soul. He states it is only his heart he gives to this Other woman. I don't understand what she can give that I haven't been able to give. I don't see the need to "have to have" someone else.
And him telling her all sorts of things about me and Us, makes me upset. There are things I wish he hadn't shared, but it is too late, and because of that she is nosey in questioning me. I can't stand it.
She tells me that she cares for me *shrugs* and that other women wouldn't even care how I felt and would only keep loyalty to him. I don't understand this.