Family Friction

I am engaged to my partner and he has lost both his parents and has one brother and one nephew. He doesn’t like the way his brother treats him but is scared of losing contact with his nephew, so he allows the behaviour of his brother towards him. I feel caught in the middle of it as I do not like his brother and the way he treats my fiance but feel like I can’t say anything as I don’t want to cause any further friction between the two.

I would like to be more detached when it comes to my fiance’s family as it upsets me and I feel affected by it negatively.

My model so far is:
C – Fiance and his brother

T- I wish it wasn’t like this

F- Upset

A- I lament on it and upset myself further. If unpleasant messages have been sent, I think about them over and over. I talk to my family about it. I stop doing things that would be good for me, like working out or even working. I withdraw from everything

R – Nothing changes with their relationship and I get further away from myself and don’t do anything healthy for me.

I am finding it difficult to do an intentional model without the thought relating to something like, I don’t want his brother in my life at all.

It would be great to see an intentional model where I am not trying to change the circumstance but am able to better navigate the situation and stay centered within myself and not feel so thrown off by everything else happening around me.

Thank You!