Need advice!!

My partner broke up with my about 10 months ago. It came out of nowhere, and I got no explanation before they ghosted me and blocked me on all forms of contact. I have been horribly struggling since then with this obsessive need for closure. For a while I continued to try to reach out to them, on my own accord or through other people, but it just kept ending with more blocking. For months, I was going through the relationship and the breakup in my head over and over, picking it apart to try and figure out what went wrong, but without a conversation with my ex, I couldn't get anywhere. I am definitely doing much better now. the compulsions to reach out to her and the spiral obsession with figuring out what went wrong have both lessened. but they are still present, especially when I sleep. I really just want to be rid of the whole situation, but i want to do it in a healthy way without locking up my feelings. i really am at such a loss though. i still want answers and i still miss my ex in a lot of ways, but at the same time, the though of running into them scares the shit out of me. ive heard some horrible things about them since then, and how they have been spreading rumors about me behind my back. the situation cant seem to get any worse and it just keep happening. and it makes my ocd triggers so much worse too. idk, i will take literally any responses and any helpful advice.

My ex boyfriend broke up with me last summer and it was really rough on me even thought we only dated for a little while. He treated me terribly but I guess I wanted it to work. However during the fall I was healing well and met my current boyfriend. I knew him as a kid and we reconnected and started dating. It’s the most WONDERFUL relationship ever and I love him so much. However for the past couple months, on and off, I have been obsessively thinking about my ex, to the point of feeling so sick to my stomach. Just the thought will do it. I have been stopping myself from checking his instagram because that just makes it worse. I do not want me ex back at all and I am so happy now. I recognize these thoughts as intrusive and hurtful. I just want them to stop and be in the moment. Has anyone had a similar experience? What did u do? Also, I want to tell my boyfriend about this but I am unsure on how to do so.

I feel like I really need help right now. I keep reminiscing on my old relationship and comparing it to my current one. For context, within my old relationship I had been with him for a pretty awful year and 3 months. Within the first 3 months I realized that I didn't actually want to be with him, but I felt sorry for him. So, I stupidly started self sabotaging the relationship. I know that it was stupid, and I tried to break up with him but every time I felt bad. His mental health was already bad and I hate any possibility that I can make someone's mental health worse. That whole "relationship" was so toxic on both ends though. All of that alone has me so messed up. But with that I also had this false attraction to him. Like, I would always be figuring out what I wanted in a relationship and tried to do that with him despite knowing that I didn't actually want to be with him. Now my mind keeps trying to convince me that I'm doing that with my current relationship. I know that I'm not. This one feels genuine and it's pretty healthy. We have our bumps, but we both have this want to fix it and it's just so nice. I hate that my brain is trying to ruin this for me.