We all go through that. In fact, we should start a seven steps to DBing list.

1) Self blame
2) Feeling like detachment will make us look like how we used to be

On your responsibility, yes, it takes two to get a marriage to this point. No doubt. However, you can't change the past. All you can do is from this moment forward be the spouse only a fool would leave.

On detachment, look up differentiation in marriage. Detachment isn't about cutting all contact, it is about not allowing his words and actions to cause you to react. Read the links Cadet sent you in his initial post in your thread. They are invaluable.

Lastly, that fear you mention in your last line shows you are too codependent. Please Google "differentiation in marriage". If you don't differentiate you will have no chance at saving at your MR, and worse, no chance of moving forward healthily.

M(53), W(54),D(19)
M-23, T-25 Bomb Drop - Dec.23, 2017
Ring and Piecing since March 2018