How interesting... There was some parts I missed because My dad kept chatting away during the heavy bits.
So Here's what I see: Lapis realizes she was the aggressor, and doesn't want to be with Jasper again since she realized how Toxic they were to each other. Jasper takes her anger out on Steven, thinking that he was the reason she made that decision. Lapis protects steven with big old water punch.
OK, context shifts a bit, but now its even more interesting. Jasper isn't just going to be simply shelfed, especially with some of the leaked titles from last month. I'm pretty sure this is going to get touched on again. But here's the important thing to get out of this: Lapis realizes that what they had was toxic and cuts the relation off there. She even says it wasn't healthy! She realizes that while Jasper put so much strain on her, she used Jasper as a scapegoat for her pain and hate, and didnt want to be in that loop any longer
Jasper kept trying to push the issue to come back, which is where Steven says to back off. No means no after all. Thats when Jasper attacked. She wasnt out to beat the evil abuser, just to protect Steven from harm.
I think many people could benefit from a couple extra viewing of this, its a really intriguing episode. Jasper and Lapis issues will come back again, I know it. We still have a lot more complexity to unearth from Jasper, so look forward to that