Okay, new perspective.
I just watched all of the LoVe scenes and it actually made them play a lot, lot better. I mean, incredibly better. Knowing what happened in between and just focusing on them added new levels to those scenes and they didn't seem rushed or just thrown in.
We went from Logan trying to get her to talk to him, her brushing him off, him showing up, her telling him, him reacting in disbelief and wanting to help, her saying that "I am going to make whoever did this sorry, even it was you" to her telling him "I am so sorry that I accused you." And him simply trying to be the best boyfriend he could be. He said he just wanted to be there for and nothing in what he said or did in that scene indicated he meant anything other than that. If she wanted to tell him, okay. If she didn't, okay. And when she did, he just sat and listened. He was truly there for her (as Wallace -- I heart Wallace! -- was, but with a different kind of emotional peace). Then from there, just a nice, relaxing dinner at his wacky dad's. Which I think was interesting on the Logan-story front because the last scene we saw was Logan back to being meanly bitter and snarky to his dad. But it was as if because things worked out right with Veronica, he was willing to try and work things out with his dad. It all just flowed: it worked.
Also, and especially, the "offness" of Logan was just not there. I remember not quite getting the making out after the party. However, watching their scenes back to back, when Logan and Veronica shut that door, he made the comment about "this is how it should be." He then continued by basically saying it should just be them, no other people. They were both just giddy. And I think that was it, why they acted that way (prior to his confession): They were giddy with relief.
They've been having this secret relationship for a couple of weeks now. The secret is out now. They didn't know how Duncan would react. They know now, it's not good, but they know and clearly they are still fine with each other. Veronica didn't know how Logan would react when/if the 09ers started on her again - note her expression when Dick insults her as if steeling herself. Well, she saw how he reacted -- unlike the last guy she had major feelings for (Duncan), this one defended her when some jackass (we'll just ignore that this one was the jackass in the first scenario) insulted her. Note her expression as she looked at Logan after he defended her.
Now add to all of the relationship stuff, Veronica knows now that it wasn't rape as she thought it was and that pressure is gone; Logan knows that she knows he didn't rape her. That pressure is gone. Finally and back to the relationship stuff once more: They've just survived a pretty huge hurdle in their relationship and are still with one another. That pressure is gone.
So take all of that in, it makes sense that they would both be practically giddy in their "we're still together! despite all of the last 72 hours+ of pain!" joy. And then it makes sense that Logan would confess then because if he didn't there would still be this huge lie (of omission) between them, just when they were just at that place of joy. And then it makes sense that Veronica forgave him so quickly because she just went through 72hours+ of pain, had a sense of peace about this enormous thing that had happened to her that while still pretty awful, thankfully, turned out to not be the horrible atrocity she's believed that it was. And she's gonna wanna keep that sense of peace longer than a nanosecond and if that meant forgiving this guy that she does clearly care a whole heckuva lot for because he was yet another domino (albeit one of the biggies) in what led to the events of that night, I can understand.
Which brings us to one last thing that made sense: The "I need a refreshment!" Right before he said that, he let out this huge exhalation of relief -- like, THANK GOD, that's off of my chest! It was like because of his confession and her forgiveness, they were both finally at a completely clean slate for the first time in forever with one another. I equate it to some major event happening, it all gets hashed out, cleared up and then there is just this moment, where "damn, I need a drink!" This was such a moment for Logan.
So it all makes sense to me now. And I do think we'll get some explanation in next week's episode that she gave him some type of explanation for leaving at the end. I think.