With OCD and ROCD the content of the thoughts is not the truth, the sufferer just can’t shake the ‘yeah, but what if…” constant doubting, which causes extreme distress. The ‘compulsion’ accompanying the obsessing is usually to seek constant reassurance, which is and never will be enough, because this is OCD and it doesn’t respond to reason. Even though rationally you know that if you really didn’t care or had real doubts, you would leave the relationship and feel relieved that it was over, not be in such distress and suffering extreme anxiety about it all, it is never enough to reassure you or bring you peace of mind.
The way out is to get proper treatment, and you are doing that with a new therapist. You seem to have a really good understanding of what you are going through and that honestly is halfway to getting well again. Your therapist needs to give you strategies to help you disengage from the thoughts, including a ‘float to survive’ strategy. Do not try not to think the thoughts, or your avoid them, it increases the frequency and urgency because being unable to stop creates more panic which leads to more worrying and reassurance seeking and in it goes. It sounds counter-intuitive, but instead of fighting and struggling to stop or avoid it, let the thoughts come, notice them, disengage from the content and label it as ‘thinking’. These are just thoughts, not reality, you can’t make what you dread come true just by thinking it, it’s just thoughts. Gradually your brain learns that it’s ok to just have thoughts, you don’t have to try to ‘solve’ them or make them go away, you can just think them, not engage and ruminate (the really hard bit, but it breaks the cycle), you can just notice that you are thinking and let it happen, then move your mind to something else that is happening in the present moment. Re-grounding yourself in the present is really helpful, allow the thoughts to float by and instead of engaging with them, notice your surroundings. Listen hard to see what you can hear, use your hands to feel your chair or table or sofa, or the water in your shower, whatever you are doing in the present moment is your friend, pull your senses to the present moment to give your brain something to do which isn’t ruminating. Ask about mindfulness cognitive behaviour therapy, that’s essentially what focusing on your present surroundings is and if you work hard at it, it’s really good, but you have to practise it and you really can retrain your brain. There are loads of good books on it, ask your therapist. Mindfulness meditation really helps any form of OCD.
A good book on OCD for me was Jeffrey Schwartz “Brain Lock” plus Google his “Four Steps for OCD.” Don’t worry too much about the difference between having ROCD or OCD, it’s basically the same thing and only the content of the thoughts is the difference. The way out is the same.
Good luck and feel free to message me any time you like, the four steps by Jeffrey Schwartz are an excellent strategy to help you.