Hawaii Five-0: Are McGarrett and Catherine done for good?

Though Hawaii Five-0 fans were eagerly anticipating the return of Catherine in the show's landmark 150th episode, they were probably hoping for some better news.

At the close of the hour, Catherine (Michelle Borth) left for a new assignment, but not before revealing that she knew McGarrett (Alex O'Loughlin) was previously going to propose — and she would've said yes! Still, Catherine expressed that while she does still care for McGarrett, she is happy now working for the CIA. Was this the closure McGarrett needed?

"I think it's over," O'Loughlin tells EW. "He's moved on. At a certain point, with any man or woman, if you go through enough with one person, you get to a point where you're like, 'Look, I love you, and I'll always love you, but I'm not taking those risks again. I did that, I was there, I sat by, I waited for a long time.'"

In fact, O'Loughlin stresses that the playing field has changed now that McGarrett is with Lynn (Sarah Carter) — Catherine even gave them her blessing. "He really likes this new girl," he says. "It would be, at the very least, dishonorable, and that's not the sort of man he is. But I think getting that information from Catherine is humorous on an ironic level to him, but it's also satisfying in a sense, because I'm sure there's a part of him, at the time that she did leave when he was going to propose, that felt like, 'Am I the problem?' It's good for him to know."

What does this mean for McGarrett's relationship with Lynn moving forward? "It probably frees it up even more," O'Loughlin says. "There's closure. Whenever we have closure, we get to move on with and take our best self with us. There's no, 'Will I see her again? Will I hear from her again? Where did she go?' He knows now."

Hawaii Five-0 airs Fridays at 9 p.m. ET on CBS.