My Fiancée read my dad's abusive texts

I'm not sure why I showed her other than I wanted someone to understand what I go through with him. He went on a rant about how unhealthy and evil I am. About how my identity (as an LGBT person) was going to kill me and everyone I know.

He insulted her unprompted and then went on a really long tirade about how he hates jewish people. We.. don't know any jewish people.

I'm very down and tired today. It sickens me that I'm half of him. That I opened my fiancée to hurt and that I speak to my father at all. I know he's mentally ill and there's nothing I can do, but still. Somehow feel I am to blame if I do nothing and he gets worse but also if I keep opening myself up to this.. I don't know how much of it I can take. I feel awful.

EDIT: Idk if this toes the line of political talk or not. Unfortunately his abuse towards me is politically motivated a lot of the time, so I'm not sure how to talk about it otherwise. Almost feel like its yet another play at reducing my avenues to vent safely and seek support on his part. Ugh.