How to stop looking for solutions with ROCD?

Hey yall. I’ve been struggling today not to spiral. For context, I’m in a loving relationship and I love my boyfriend dearly. However, I struggle intensely with thoughts about his past intimacy with his ex, especially considering I have no past. I grew up in a very sheltered religious environment so thinking of his immorality affects me deeply. I’ve come to accept the matter and see the purity of his heart instead of body but I still compare myself to her, think she loved him better or more, think they have a “soul tie,” hate that I’m not his first love…etc. He has changed so much since then and because we’re religious, thinking that he is “redeemed” helps sometimes. He tells me that what he did with her was shrouded in sin and coupled with shame and because of that, it feels nothing like the pure connection we have. But still, since I’m a virgin I just don’t get how you can do that with someone and not be genuinely emotionally present or not think of them constantly. Can anyone with more experience shed some light? Most days, I wake up just trying to convince myself that she doesn’t matter in our story and she’s not relevant to his. I know the past has shaped him to become the person that I love but when I think of him with someone else it just drops my heart to my feet. On days when I’m deep in a pit of anxiety, I feel like I’ll never get over it and that must mean we’re not meant to be. Breaking up feels like the way to finally stop the anxiety, even though we love each other whole-souled. I keep ruminating on it because I remember a time when I was able to think of something that stopped a spiral. How do I think of affirmations to stay in the present and realize her insignificance (free from contempt), without ruminating? I need to figure out how to be okay because I can tell he’s getting emotionally drained. He’s so strong but eventually being around someone so doubtful rubs of on yourself. I make him feel like he’ll never be enough for me. What should I do??