Family vs. Relationship

So my family (that I can't stand) is going through some really rough shit right now, and I am expected to be present and help and be part of it. But my partner disagrees with this and encourages me to take control over my own life and make decisions for myself because I want to make them, not because I feel obligated to do anything for anyone else. I feel like I'm failing both him and my family and I have no idea to balance the two. All of this is very complicated and difficult... suggestions for how to choose between the two of them; family that I hate vs. my relationship.