How do I resist performing a compulsion? When it comes up it genuinely feels like i want to do it so I do and check if I like it and when i don't I move on but then the same thing happens over and over. it feels real and true which is what makes me perform the checking compulsion. I can't tell if it is an urge or something I want so i don't know what to do or how to respond.

What helps me is realizing that a compulsion is happening. I tell myself that I don't need to know whatever the OCD is pestering me about, or sometimes I turn it into ERP and agree with it. "Yes! My partner and I are DEFINITELY not meant to be, we're toxic for each other" etc etc.

I just tell myself that I'll worry about it later. My OCD has gotten worse again recently and just like you, I WANT to go over my memories and check and look for stuff and imagine the future, in the hopes of finding some clue or angle which reassures me my fears aren't true. You're quite right that doing so doesn't help, it keeps things going, and makes me ill in the meantime. For me, it's both an urge to check and then a desire to follow the urge- and of course I want to follow the urge! It's OCD! It feels like I need to, like it will solve my problems, like it can make me feel better etc, plus on the flipside the idea of not checking is terrifying because it feels as if then I won't be safe or know and I so NEED to know. And yet at the same time even if I get a comforting answer from my checking, it doesn't last because it feels like I'm deluding myself that my fear isn't true based on just one possibility. It's all OCD. Telling it you'll worry about it later as often as possible is my go-to. It makes the urges less strong and can even make my belief that I ought to follow the urges less strong and make me more open to saner, less black and white interpretations of my fears or themes. Tbh I wouldn't be able to deal with my own themes right now while I'm in it if it wasn't for my therapist so I strongly recommend getting one.

Hopefully that helps! Be consistent and patient with yourself and you'll start seeing changes.