I cannot report my assault - How can I allow myself to move on and get closure?

Unfortunately, due to various circumstances, I am unable to report what happened to me.

My assaulter is still intertwined in both my personal and work life, they're friends with all of my friends, they're basically a coworker, and I will have to see and work with them for the foreseeable future.

Without writing 500 paragraphs for context and explanation, I'll just say that reporting it and bringing it to people's attention will only cause more harm than good for me. It's not that I don't want to report it, I just can't.

I've never felt so alone. I feel like I can't tell anybody in my life because of how intertwined this person is with everything. Not even sure if they'd believe me.

So where do I go from here?

How can I move on/get closure? I can't spend every single waking moment ruminating about what happened to me. It's only causing me constant pain.