I also think that scene was dead on accurate emotionally. I don't think he would have gone quite so far, though, if not for the fact that Vala had been tormenting him for three months when he got to that point. The thing with the handcuffs, and probably hundreds of things we didn't see, really amplified his suspicion that she was only teasing him for sport. And of course he wouldn't have exploded if he didn't truly care for her, and hadn't already thought about the reasons they wouldn't work, and then had them shown to him in the form of said teasing.

In short, this moment will be a lot less explosive when it comes in the new timeline.