Well, like I suggest quite often on here, and as this kind of triad arrangement seems to go south pretty fast.... become a vee dynamic and get your own girlfriend.
Triads seem to be the hardest configuration in poly relationships. The dynamic is set up so that there seems to be a third wheel most of the time. There is no reason to stay in that if one person is feeling left out. If they are more into each other then let them be and don't be involved any more. Sometimes people in their NRE think that it would be hot and sexy to be three and it can be fun to be that for awhile, but it seems that at some point there is a natural break and its time to change and rearrange things... so go with it and do it. There is nothing wrong with that and it doesn't mean that you are any less loved or cared about. It just means that the dynamic in terms of "partners" is not working any more.
So why not create a beautiful metamour relationship and find your self some one that you can create a girlfriend relationship with... I know, sounds so simple and it would be great to just wave a wand and all the emotions to just disappear... just think on it and keep it in mind, I find it so hard to listen to people struggling to hold on when really, letting go would keep them from the pain and torment of situations such as yours.
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