REVENGE.
He had done it. He acted on his revenge. He caused so much damage. He caused so much conflict. He made her numb more than ever. Hearts were broken. He had decided, "No, I'm not gonna let her stay. I'm not letting her walk." Worst of all?
He left her in fear.
What has Ralph done? He almost fucking killed her! All for just trying to keep her with him? STUPID! He couldn't believe what he had done, and now look at this, she no longer wants to be with him. Vanellope, his best friend for over 6 years, whom he has trusted ever since, wants to be away from him. She no longer has his trust within her anymore. She views him as his enemy. The bad guy he once was.
"You took petty on me, Ralph. You think I wanna hang out with a friend like you? No! You're an asshole for this!"
Was the act of Revenge even worth it? Did it just happen to make things worse? Did she really mean that she doesn't want to be with him anymore? Let me answer these questions for you; No, yes, and perhaps. What would happen after all of this? I don't know.
Vanellope could do the same shit as well. She could seek revenge to Ralph. She could potentially put him in danger, hell, even kill him. No, she shouldn't be doing that. If he only wanted to keep her with him, what's the point of hurting him more? He's already hurt from the act of revenge he had sought upon her. That act of revenge was the worst mistake he had ever done. She's not going to make it worse than it is already.
Not only Ralph had harm himself for this, he had harmed another one as well. But who should rot in that grave after this? Of course Ralph, look what he did, he almost killed Vanellope. But he did this out of fear for a reason. Vanellope almost left Ralph for another one.
So both should rot.