Hi, sorry I had missed all this!
OK here is my opinion. I have NEVER had an aggressive society finch, and that's why you don't find it online. They just aren't. However - you know that often societies and zebras are cross-bred, right? So I think he has just enough ZEBRA in him to act this way. He wants to mate and she's saying no, I think. If you'd put him in a zebra finch costume, we'd all say "totally normal." Little buggers.
I'm assuming you don't want to buy more finches and re-pair them with a different mate, and you don't want to separate them and have 2 lonely birds. When I had zebras (I quit them because I can't stand aggressive behavior) I would either hang LOTS more fake plants in the cage to sort of visually block the aggressor, or I'd put more cages side-by-side with the sides removed/ziptie the cages together. Or both. That way she can get away and he might get distracted during his search for her.
Another thing, this will be hard to explain, I took round cardboard rolls (like the center out of a roll of ribbon, only bigger, 4" diameter and perhaps 3" deep) and hot-glued 3 side by side. So three circles. OOO
Then I hung that against the side of the cage. Birds that got chased could sit in them and sort of hide. Effective, inexpensive, and you can toss it when it gets dirty.
I believe this will settle down once they quit the eggs, but please know that finches CAN harm one another, and can kill another bird.
They're probably getting tired of egg-sitting now. Once they aren't on them so often, just pull them out.