RSBM.
In fact,
a lawyer isn't needed for most divorces. Do it yourself divorce forms are readily available. I think the Morphews' situation was not terribly complex. SM could have written the terms of custody, child support, spousal maintenance, and property division herself. But most people in her position would want a lawyer to assure it was done right.
Nearly all mediators are also attorneys. If not, the mediation firm has has an attorney available. If BM had agreed to dissolve their relationship in a civil manner, a mediation firm would have been a logical choice to work out the details and write it up.
I agree that meeting with an attorney would be a logical step for someone who is ready to divorce. But it isn't an
essential step to make the decision to divorce. Especially if you are afraid your husband will kill you if you try it after MM2 graduates HS and moves out of the PP residence. SM's decision to divorce, expressed to BM in Spring 2020, was prompted by such a fear.
I find the evidence compelling that SM had decided to divorce BM, that they had discussed her moving to a separate residence with MM2 during her last HS year, and that she was telling him she was ready to take the next step in her "I'm done" text. The next step, a civil discussion of the terms of divorce, would most likely involve a mediator or - if they agreed on all the terms - a lawyer to draft the documents.