This has to be sooo frustrating. Despite your best efforts, you haven’t been able to manage this on your own. You may be right on target thinking that what you are experiencing is a symptom of OCD. Many people mistakenly think that OCD is only about hand washing or checking things over and over or putting things obsessively in order. But OCD has many forms and differs from individual to individual. In some people, and maybe for you, it takes the form of repetitive, unwanted thoughts. It’s certainly worth getting an evaluation to see if this applies to you.
All therapy is not alike. If you’re right that OCD is the culprit, going over your childhood experiences or analyzing your current situation probably isn’t going to help. If that’s the diagnosis, I would suggest a two-pronged approach: See a psychiatrist about some medication (yes, there is medication that helps tone down OCD) and find a cognitive behavioral therapist who can teach you about “thought stopping.” You live in a very big city. I’m reasonably certain that you can find a clinic that offers a sliding fee scale and that has evening and weekend hours.
I hope you follow through, both for your own sake and the sake of your relationship. Your boyfriend has been terrific so far but I agree, if you don’t start to handle your problem differently, he could start to wonder if he wants to sign on for a lifetime of listening to your issues.
I wish you well.