Well done on starting a new thread, Poet, if anyone is bored of you they don't have to join it. The vast majority of us are not bored of you, we want to support and help you and your children.
"I am not sure why you said earlier that you would save it (sex) for me for later - we are having a break from sexual activity, so we won't be having it later. To be very clear: I don't want to have sex, or any sexual contact, tonight or over the weekend or until I let you know otherwise. I don't want you to try to convince me or to start any form of sexual contact at all."
I would suggest that you send him a message like this, but I don't think it will help. We all know (you included, I think) that he is planning to rape you soon whatever you do. The problem is not that you have not been clear enough or that he doesn't understand. The problem is that he likes raping you.
When you say that you intend to stand firm on your no, what exactly do you mean by this? What will you do when (not if) he starts pushing your boundaries? I am not blaming you at all, I just don't want you to be unprepared for what is going to happen.
I have never, ever feared that my husband would explode. You, quite reasonably, do fear that yours will - because all of his previous behaviour indicates that he will. Thus far he is able to control you by exploding somewhat rarely, because you are (understandably) so afraid of him that you do as he wants to try to prevent further explosions. If you try to hold your boundaries he WILL ramp up his behaviour in response.
This happens already in your sexual relationship: he is able to regularly rape you using only the threat of (worse) physical violence, because the times he has used violence particularly severely during sex let you know that he will do that again if you try to stand up to him (although there are very often aspects of physical violence even in the sex that you instigate yourself as a way to try to prevent more of the more violent rapes).
You are already stressed and anxious because you know what is coming. Please reach out for more support from your family, friends, colleagues, WA, police, wherever you feel able to.