If you are at the point of being done, why meet and talk to him? What good can come out of that?
So no, I do not think you are right to instigate the meeting. If you really are done with him then there is only one thing to do:
File for D.
My guess is that you will recoil from that advice because a) you are not ready and b) your wanting to meet with him was another effort to get him to change his mind.
As far as OW, why are you allowing her to have control over you? Here is the thing. She is meaningless. She doesn't matter. If it wasn't her it would have been another woman. So she just doesn't matter. She only has the control over him that HE gives her. So this is all on him. Now, your issue is the same. why are you allowing her, through him, to have control over you like this? Don't waste another moment of thought on her. She isn't the problem.
M(53), W(54),D(19) M-23, T-25 Bomb Drop - Dec.23, 2017 Ring and Piecing since March 2018