So, what I did was the "partial divider" trick. The female is smaller than the male by enough that with some trial and error, I was able to make a hole in the divider that she can get through but he can't -- I think.
So she went through the hole to his side of the tank and they're swimming in circles and shaking and carrying on. But, no real violence. So, I guess I'll just let it go, see what happens.
I assume she's slick enough to run back to her side through the hole if he starts beating on her......