I’m sorry that you’re dealing with this. :( I completely empathize with your story. I’ve been dealing with ROCD myself for a while now as well, and while I’m really new to receiving OCD treatment, I did gain a lot of insight from a book called “The Mindfulness Workbook for OCD” by John Hershfield, if you’re interested in checking it out! It goes over this specific subtype, too.
Since I’m not a professional, of course take my word with a grain of salt, but something that I learned from that book is that the act of self-reassurance and rationalizing are mental compulsions. To me, I think from what you’re describing at the beginning of your post as thinking of your thoughts being untrue, is a mental compulsion. And it worked because it brought you some peace from the anxiety but it doesn’t work anymore because your OCD “learned” that trick, if that makes sense. Now, you’ve got yourself thinking in other ways of how you don’t have attraction to your partner. Honestly, the way to conquer this feeling is by acknowledging your thoughts of no attraction and not engage with it mentally. This doesn’t mean to ignore it either, as that is also a compulsion. This is, admittedly, *really* hard to do, and would be more helpful with the guidance of a professional, but the way I was doing it was by realizing I was having an intrusive thought about my relationship and I would think, “oh hey, there’s that thought. I realize that it’s here, but I’m too busy doing something else right now to try to figure it out. This thought can stay here if it wants, but I’m not going to stop what I’m doing to help it out”. This process is not really going to get rid of the anxiety of the thoughts occurring and unfortunately, that is the point. You have to train your brain that these thoughts are harmless, not-urgent, and that your brain and body CAN tolerate anxiety until it naturally goes away without compulsions. I would recommended reading about that process further, which they do a wonderful job in the book I referenced earlier! :) It’s where I got my most useful info from.
As for the attraction to other people, I know you said you cannot tolerate the thought of it being normal, but in my opinion, I would encourage you to also sit with that discomfort. While, of course it may feel uncomfortable to realize that somebody other than your boyfriend is attractive, you do have control over your choices. You are right, you do not have control over the realization that someone has an attractive look or personality, but you do have control over your actions and whether or not you do anything about your attraction to any person. You’ve already been making the conscious decision to be with your boyfriend every day despite your anxiety around this, and that is already very strong and brave of you! You can do this because the anxiety is temporary even if it lasts a while and you’ve lived through all of the anxiety you’ve had before.
Sorry for such a long-winded reply, and like I said, not a professional here! But I know how you’re struggling, and still struggle with it myself, but it does get easier to identify and live with and with professional help, I believe it’s something we can both see the other side of. :)