Cheating OCD - need help

So i play in a band, and we were having practice, and my girlfriend was there listening to us, then this girl around our age walks in, and my head tells me to cheat on my girlfriend with her. I know i would never do such a thing. And it bothered me for days. And i ended up telling my girlfriend, and tried to explain my ocd. It hurt her and she believes that the instrusive thoughts, are my thoughts so in that, i must feel something behind them. And she feels hurt because i explained to her the obsessive part of ocd and how this thought wouldnt leave my head. And she got upset knowing that i was constantly thinking about cheating on her. I cant help but feel its all my fault. And now that she doesnt understand i feel really guilty for my thoughts and they are coming more often and worse. When i was fine for months, but my ocd always acts up right as i get in relationships, then i usually tell my spouse and tell them i cant feel guilt for my thoughts or they will get worse. And they usually just accepted it and it was easy. But with her it seems she just cant seem to understand, ive tried to explain it to her countless times, she isnt willing to do research with me to help better understand it or anything. Maybe for my first ocd issue telling her that wasnt the best idea.

Hi, I'm 17,about to be 18. I've been struggling with these thoughts for the past 8 months. I was wondering if someone experienced ever the same because I feel im "different". BACKGROUND: (I'm not diagnosed with Ocd but seeing a local counselor) About 9 months ago I cheated on my boyfriend with this guy S (who blackmailed, manipulated and molested me). Since then when I realized that what i did was very WRONG and so I started ruminating picking apart every single interaction and telling my boyfriend, i tried to remember every single detail because otherwise I felt like i was being a fraud and hiding things to save myself, i had many crisis about it because I had also what i think was false memory ocd. My boyfriend forgave me idk how tbh I still wonder. CURRENT STRUGGLE: Months ago I was sure I didn't wanna S in any way and i was sure even when everything happened. For the past 2 months tho I've been having thoughts like " Do I love S?" "I love S" "S is hot" "Would S find me hot?" "What if I want S?" " What if I don't love my boyfriend enough?" "What if I secretly want S?" "What if I see my boyfriend as a friend only?Do I?" And I tried testing my reaction to intimate scenarios with S, I'm scared I like it i dont really wanna love S or have any secret attraction, I wish I didn't have any of this and I want to be sure of my feelings for my boyfriend because I know I wanna be with him and I see a future with him like he brings me comfort. But a part of me keeps trying to convince me otherwise. Sometimes I think I'd rather die than have these thoughts. Im so scared of not being able to control my feelings, im scared I can't resist S and its giving me anxiety and making me cry. Sometimes when i think of those sexual scenarios with S or I get those thoughts my mind tells me to smile because i like it because I find it funny. It makes me doubt myself all over again. Like I'm always like I need to test if I'd feel aroused to intimate scenarios with S, lately im trying to fight this urge to test and test but my mind is like "just do it this once so you can be sure. I can never watch anything romantic or sexual or whatever because my mind would be like "you and S" or sometimes I'm just enjoying time with my bf and im like " yes we can just have a sneaky cheating thing thats ok" and it makes me want to figure it out to find an answer a solution because idk it just does like I need to find the meaning of it if it means the truth and all. Im worried im just an awful person and these thoughts just ruin my quality of life . Today i had a crisis where i ended up doinf swlf harm, I'm so scared of finding someone that's not my boyfriend desirable or sexual appealing or whatever it is, I also have bodily reactions when I try to imagine and test my reaction to scenarios. Now i keep groing everytime and I dont know why but i have this sensation and I dont want to havebit especially when its something S related. Does someone experience the same thoughts? Am I alone in this? Is this ROCD? What should i do?

I was doing fine today until I asked ChatGPT if i cheated and they said it could count as emotional cheating if you are engaging in intense daydreams and looking someone up on social media to feed a fantasy about them. My partner and I already spoke about me fantasizing about this person and he said it was totally fine since it happened in my head and he has had crushes and fantasies on coworkers too. However I feel absolutely devastated and wrecked with guilt and anxiety and panic right now. I genuinely feel like a horrible horrible horrible cheater. I don’t know what to do. I have therapy scheduled for later this week but I really really need some advice right now!!! I feel like it could count as cheating since it did happen during a few weeks where i felt a bit distant from my partner and I feel like the daydreaming was excessive. I am so so scared. Do I confess? Do I tell him I cheated? He already told me once that cheating is a physical interaction (and I literally have not interacted with this person outside of surface level responses in a group server that my partner is also a part of). Do I have a moral obligation to tell him I cheated? I need to know.