I can relate to your situation. It was much worse for me the closer it was to DDay (the last of our DDays, to be exact). I felt really down on myself when I couldn't 'perform' with my WW, especially with mind movies going, etc. But then something snapped in me, and I no longer feel down on myself.
This is what it was. I actually stopped for a moment and thought about what I was feeling and why. I felt like I was trying to be intimate with someone who has violated and hurt me in the most profound of ways. And it was no wonder I was 'protecting' myself, and had a mental block with her. Intimacy is a very close thing (for most), and it's incredibly hard to try to be intimate with someone who has wronged you on so many fundamental levels. It just is.
As a man, though, I can totally see how you may feel down on yourself for the 'performance' thing, I know I did. But again, something just clicked inside me one day (couple months ago, I think?) where I no longer cared or felt responsible for performance issues with my WW, because I realized that the performance issues were solely with her. That is, I would have absolutely NO performance issues with anyone else. That made me feel that the issue wasn't something with me or 'wrong' with me, but lied with her. Ever since that realization, I no longer beat myself up anyone over that topic, or try to take control of the situation. I just say to myself, "well, I can't perform because you've really hurt me, and I just don't feel that intimate toward you right now".
Also, in terms of mind movies, those have almost completely stopped. I attribute this to the fact that after really seeing the OM my WW was cheating on me with (pics of him, learning about him, etc.) I can see that he is absolutely hideous. Like really fucking nasty looking. Ever since realizing that, he is the absolute last person who would ever enter my mind in that sense. Not sure if that's helpful or not. Thought I would throw it out there just in case.
Really try to find the source of the control you feel you need exert over the intimacy situation and see if it is similar for you. It likely is. And if so, once you're able to identify with it, you may see what I saw, and something might just click within you, too, in that same way.
[This message edited by Theradin at 12:18 PM, April 29th (Monday)]