My 26 sister is dating a 19 y/o and I'm worried if I disagree she'll tell everyone I'm a zoophile/zocd

This is a genuine worry I've been sitting on for a few days. I am in therapy by the way! So I will get 100% clear advice from her this week. But I just needed a place to speak and get others advice since this topic seems very... difficult. Also I'm 23.

My sister is 26 and is dating a 19 y/o. Theyve been interested in one another since February when he was 18 and she was still 26. When he hit 19 they,,, they began dating within a couple weeks.

There is so much more wrong about this, its really complex that I'll need to speak to my therapist about so please avoid speculation on it.

My post is about *me*. It took me two years to get into therapy for my zoophilic OCD and my mental health has been horrible for the last 8 years because of it. I'm still having a difficult time accepting I have OCD, but I did let my sister know about it after months of therapy and building up.

I don't trust her. I still regret ever saying anything about it no matter how respectful she is about it and despite the progress she's made I know her. She will turn on a dime if I do something to make her mad and make me her least favorite person (shes bipolar ^^;) She's grown a lot over the last couple years, but I know her. My distrust doesn't come from no where.

I'm really worried that if I need to speak up against this in any shape or form, she'll lash back out and tell everyone about me being a zoophile and being attracted to our old dog and so much more. I am genuinely uncomfortable with their relationship after meeting him, but if it does feel abusive I will call it out the best I can and voice my concerns.

I know I will not be able to mentally handle the situation at ALL. I'm debating contacting my therapist about this worry, shes chill with it tbh. I am doing good with avoiding compulsions and just accepting if something happens then it happens and I will handle it in the future.

But I am looking for support, advice, and comfort. How would I even navigate this confusing of a situation if it does transpire? What would you do? Has this happened to anyone else???