User blog comment:Hyperborean/What to expect/@comment-4515675-20120514060830/@comment-5112532-20120519092108

RR never said Jason and Reyna are in a romantic relationship, but it is implied that it was beginning to develop along those lines...and I quote: 'We might have been,' Reyna said, 'given time. Praetors work closely together. It's common for them to become romantically involved.'

So I don't think Jason is acting ridiculously since the Mist has twisted the truth, with Piper believing he was her boyfriend, and they went on a quest together blah blah blah so they've obviously bonded over time.