Joe Mantegna, Isabella Hoffman

It only took four years, but Joe Mantegna finally got his Criminal Minds wish.

"I've been campaigning to meet [Rossi's] ex-wives since we've established it in the third season," Mantegna tells TVGuide.com. "I've even campaigned for an episode where all three show up. How diverse would they be? I didn't want it to be like, you go to a play and they have a shotgun hanging over the fireplace. Somebody better grab that shotgun and use it by Act 3. I laid that in there with the producers about having these three ex-wives for so long: 'I think it's time we addressed that.'"

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Mantegna, not to mention fans, will have to wait to meet all three. It will just be ex numero uno Carolyn (Isabella Hoffman) who drops by Wednesday's episode. Visiting from San Francisco, she's seemingly there to catch up, but she is actually there to deliver some news to Rossi.

"It's certainly very surprising," Mantegna says. "But it's realistic. I think the fans will be satisfied as I was with it. It's got everything. It's bittersweet. It's got the good, the bad, the ugly, the sad. ... And I think we came up with a really good story for a way to introduce that aspect of his life, which may now make it that we never know who the other two are. It's that complex."

Carolyn's bombshell — which is unrelated to a case — is only the half of it: She also asks for Rossi's help in the matter, which will spill into her second episode, airing Nov. 2. Rossi will struggle with the choice, Mantegna says, as it's not one that anyone could arrive at lightly. "It's not black and white at all," he says. "That's why it covers two episodes. It's not the main story line, but it gets its proper due. I think it would be a disservice if it was wrapped up in one. He needs to put some thought into it. This wasn't something he was expecting."

What Rossi was expecting, on the other hand, was possibly giving it a second try with Carolyn, even though we all know the only people he makes happy are divorce lawyers. But as the saying goes, "You never forget your first."

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"There's a scene I do with Paget [Brewster] that intimates that the 'first is always the most unforgettable' type of thing," Mantegna says. "[Carolyn's] got a little — I don't want to say mileage — but she's got some history. It's been 20 years [since they divorced]. I don't think he can help having feelings again. I think that's the universal thing that happens to people in general. ... He hasn't had a lot of contact with her, so it's like, what's it going to be like? People change, things change. The years give you a little perspective on all that, but bottom line, if there was a strong attachment like that in your life, you shouldn't be surprised if remnants of it are still there. You remember what you had and what you were, but now you have to deal with who you are and where you've gone and what you've become."

Still, Rossi doesn't make for an ideal partner, given the demands of being a profiler. And then there was the implication — also made back in Season 3 — that he's a womanizer since rumor has it that BAU fraternization rules exist because of him. Why Rossi and Carolyn split is not revealed, but Mantegna suspects it has more to do with his professional lifestyle than anything else.

"I give FBI agents, policemen — all those people — such respect. It's a tough world to be a part of," he says. "It's not like she hated golf and I couldn't stand it. It took him three tries to figure out that he and marriage don't fly. I don't think it matters why they divorced, but you can see there are no hard feelings. I'm just glad that we can show this part of his life now that we're seven years in and you're invested in these characters."

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Meeting Rossi's exes isn't the only thing on Mantegna's wish list. There is one other Rossi backstory he would love to delve into: his military background.

"We're alluding to it now somewhat in these episodes, but there's a whole other backstory there," he says. "Part of it is because of my age. I am a bit older than all the rest. I have a very close attachment to the military personally and I just think it's important. I grew up in the Vietnam era and I knew what it was like to have vets coming home. I think we'll do it. I think it may happen this season. I hope so. I've been here coming on five years. It took me that long to get the wives on!"

Criminal Minds airs Wednesdays at 9/8c on CBS.