No 2x4s here. You stated your truth and your boundary. You didn't cry or beg or plead. I think you did great.
The only thing now-- and this is really important-- you stated your boundary. If he can't commit to working on the MR, you can't continue in limbo and will take the next steps. You HAVE to stick with this.
What are the next steps you are going to take? I would recommend focusing on those, planning them out, and get ready to pull the trigger if needed.
Also-- what does he need to do to show you the "smallest step" towards MR? (I mean, I guess if I was going to give a 2x4 it would be here-- that is a pretty low bar for him to meet and I can definitely imagine situations where he feels he is showing you the "smallest step" when in fact you are still in limbo and feel no better.) What really is your line here and how will you know that he's serious?
((SAGE))
Me (46) H (42) M:14 T:18, D9 & D11 4/19 - 12/19: series of escalating BDs 9/20 - present: R and piecing