I've only started to feel the weight of how flawed my relationship with DM is since DP raised it as a very odd dynamic to him.
I grew up as an only child. We didn't have much other family. She told everyone we were 'best friends' from when I was around 5 and bragged about it to everyone. I remember in childhood thinking we were best friends but looking back, she had a real lack of patience and lost her temper with me a lot of the time. I watched a lot of emotional outbursts and from a young age, knew what was going on in her dating life and often comforted her when those relationships would break down.
In adolescence and teenage years, she still tried to tell everyone that we were best friends but I rarely told her anything because her reactions were often unpleasant and I'd started resenting her because of how I felt I was treated.
When I met DP and had children and got on amazingly with his family, she always seem slightly bitter and made comments about how she'd been 'left alone'. She makes negative comments about DP and his family to try and put them down. She makes comments about me never making time for her now I have my own family. She has no friends and has had no relationships since my childhood and the bit that flags red to my DP is that she constantly messages me her negativity, complaining about life and discussing her mental illnesses - she still brags about our closeness but I feel like I'm her personal therapist.
But in turn, as a habit, I feel like I communicate with her just as much and I'm dragged down to her level, complaining and whining to her and being involved with the negativity.
Every single time I think about cutting off this unhealthy pattern, I feel so much guilt for her because I'm the only person she has that I can't cope with it.
What do you even do in this situation?