How do you process getting divorced?

Throwaway account. My partner (she/her) and I were married young in the church (I’m now 23f). We left the church maybe 2 years after getting married and have been out for a few years. We are still best friends, but we’ve been through hell together and are growing up. We want different things in life. We’ve been to marriage therapy and we know that our marriage is coming to an end. We just don’t work as a married couple and are both unhappy. We mutually decided to separate.

I am crushed. Absolutely devastated. I don’t have words to express my hurt. I can’t believe it’s come to this, but at the same time I can. I love her and she loves me. But how on earth am I supposed to process getting divorced after everything we went through together? How do you step into a new chapter? I’m so so terrified that we’re making the wrong decision. I’m scared to be alone for the first time in my adult life. But I know I’ll continue to be unhappy in this relationship. We really are just friends. Any advice…? These feelings are so confusing…