Relationship triangles are common when Venus aspects Pluto. There is often a femme fatale involved in some form. She may be in the flesh. She may live in the memory of one of the parties or in someone’s paranoia but one way or the other, love becomes psychological.
I notice, while there are three players, there is more than one game being played.
To illustrate, I have a client who has been seduced by an entity online. They have established a relationship. I am coming in from the side, with a harpoon. The same woman in the same relationship has a sister who is coming in with her harpoon. My guess is she has some friends, also armed with harpoons.
Not everyone is going to want to stab in the same way, in the same place. For example, this gal has a relationship with me, an astrologer. Someone might want to degrade (Pluto) that!
Got a triangle going in your life? Tell us!