I use a pen name for almost the same exact reasons you do.
I also struggle with severe OCD, mostly of the guilt + contamination varieties. It’s more severe than I like to let on, and I do talk about it from time to time in my work. But I do not want the details about that struggle to make it back to people I know in real life. The pen name helps achieve that.
There are other reasons I use it, both personal and professional, but the OCD is the biggest reason. Fortunately, I don’t feel bad about it. The way I see it, as long as my writing is honest and sincere, it doesn’t really matter what name I attach to it. At least, that’s what I tell myself!