You know that reconciliation shouldn't look like rugsweeping or you propping up the marriage or him falling asleep when you are communicating something important and heart-felt.
Three years out is a good time to take stock of your progress toward reconciliation and of your marriage in general.
Do you feel safe emotionally?
Do you feel supported?
Do the two of you communicate deeply and regularly? (Is their emotional intimacy?)
Would you feel better alone than together?
You seem to be assessing the situation clearly.
You could ask for separation and see what that feels like. Of course there is no guaranatee that he will agree, and, if he does, there is no guarantee you will ever come back together.
However, space can be clarifying for both of you.
If he suddenly scrambles to do some work or be supportive, don't trust that as a permanent change until the changes become engrained.
In my own relationship, I've said that the changes I would need to see in order to stay need to become "the new normal." While there has definitely been work and progress on my husband’s part, we are not at the level of engrained/permanent changes yet.
I support you as you continue to evaluating your situation and make choices about how to proceed.