I Don't Blame Vicki
When you love somebody, you can forgive (or maybe just forget) even the worst of lies told. But as others have said, because of the show.. it would be career suicide if she stayed with him. I don't blame her for wanting to get even with these people.
Even if he was lying, the amount of effort they put into trying to essentially force them to split was astronomical. The whole season was everyone trying to break them up basically. They knew if they could prove he was lying then they would not be together any longer.
I'm not a person that wants REVENGE at any cost.. but I do find that I MUST GET EVEN when somebody wrongs me. If I don't even the score, it throws off my whole game. It destroys my confidence & sends me into a depressed state that is hard to come out of. Getting even ASAP keeps me strong and willing to forge ahead in this difficult world.
I see some of those traits in Vicki as well. Obviously people are not going to like somebody that always has to get even, saying they should take the high road & ignore it. But doing that isn't an option for some people. They'd never bounce back from getting knocked down. So they fight back at whatever cost.
Just how I see it.. -shrug-