Stuck between friends in toxic relationship
Earlier this year I became friends with someone who I was introduced to by a coworker. We'll call him Joe. Initially, Joe's and I's conversations revolved around common interests. They are a huge gym rat and decided to take me under their wing to help my workouts. This is what introduced me to his girlfriend, who we'll call Sarah. Over a couple of months, I started to realize that Joe has severe narcissistic behaviors that were starting to really shine through. What I had previously thought was genuine help from Joe started to make me feel like I was a project to him. Constantly being told what areas of my life I need to improve on, and eventually feeling degrading. This is how Sarah and I started to bond over the absurdity of his tendencies.
She is what I consider to be a normal person, at least in comparison to a narcissist like Joe. There was a distinct point in Joe and I's relationship that he felt like he could open up to me about how unhappy he was with Sarah. He even gave me a timeline as to when he is breaking up with her, so it's clearly planned out. Because I was his friend first, I felt like I needed to provide some sort of validation of his feelings, even though I thought they were dramatic and unreasonabke. At this point, I started to feel awful about what I was hearing said because I know how good of a person Sarah is. I recently left a long term relationship and can understand how awful it feels for one person to have an expectation that the other clearly doesn't. I constantly see him manipulating her into thinking they have a future together when he tells me he hates her and doesn't want to be with her. It's left me with secondhand guilt when I'm around them both.
As time progressed, Sarah started to figure out that he's emotionally abusing her more than previously though. This has resulted in me basically becoming the therapist for each of them. Realizing that I've gotten myself into this situation, I tried to put up boundaries with both of them to not talk shit about the other person to me. Unfortunately, it hasn't worked and I still feel like the mediator. I honestly wish they would break up asap to just rip the bandaid off. I've never been good at cutting off friendships, especially when I see the person(s) nearly everyday.
My main dilemna right now is I enjoy having Joe as a gym partner, but on a friend level, his narcissism is beyond tiring. I appreciate Sarah as a genuine friend because we have a lot in common, but I've been told by Joe that I'm not to see her if (more like when) they breakup. I feel like my mental health has suffered from being a morally decent person who just wants them both to understand how damaging it is to be together. Joe is a master manipulator and Sarah is very naive so I expect they'll keep doing this song and dance until he's done using her. I just hate having to be on the sidelines watching it unfold as their relationship is built on lies. I'm at the point now where I feel like I'm just having to be friends with Joe because I'm using him for discipline and motivation at the gym. I'm not sure what to do with this triangle I'm stuck in. I wish I had set boundaries early on, but I can't go back in the past. Having the knowledge of what Joe confides in me makes me feel empathetic for Sarah, so maybe I just need to stay away from both of them until they inevitably split. I've tried to be the voice of reason but it's not my place to make someone leave an abusive relationship.