The Big Bang Theory is kicking off Season 9 with a wedding and a "divorce" of sorts.

While Penny (Kaley Cuoco-Sweeting) and Leonard (Johnny Galecki) are getting hitched in Las Vegas on Monday's premiere (8/7c, CBS), all is still not well between Sheldon (Jim Parsons) and Amy (Mayim Bialik), who wanted to take a break to reevaluate their relationship in the Season 8 finale.

"I don't think it's a spoiler to say they don't make up by the end [of the episode]," executive producer Steve Molaro tells TVGuide.com. "It's rough on both of them. I think [it's] like a divorce in the beginning and it's yet another thing that Sheldon and Amy and all seven of them need to navigate separately and as a group."

And despite Lenny's nuptials, it's not exactly happily ever after for them either, since Leonard had just confessed to kissing another woman, Mandy, on his North Sea expedition two years ago. "Some might say it's not a good idea to get married right after that," Molaro jokes.

So what else can you look forward to on Lenny's big day and Shamy's bad day? Find out below!

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1. Technology to the rescue Penny and Leonard's wedding is hardly a splashy affair, taking place in what Molaro describes as a "small and slightly depressing Vegas chapel." But don't think the rest of the gang will miss their pals tying the knot. "Like many Vegas chapels do these days, the weddings are available to be streamed online, so that's how they can watch," he says. "Technology is our friend here. We always wanted everyone to be part of it somehow."

2. I do... not have vows While Leonard is prepared with his own vows, Penny is put on the spot to come up with hers, which you do not want to miss. "She had no idea there would be vows ... and what comes out is truly wonderful and lovely," Molaro teases. "Kaley was just remarkable and so good at it. It was one of those things where I was so excited about that I had told her weeks before that I was really excited for their vows and she was so cute, like, 'Don't tell me. I wanna read it on my own.' She just destroyed it."

3. The other woman The honeymoon is over quickly for the pair when Penny brings up Mandy on their wedding night. "Leonard tries to diffuse the situation, but it's clearly not working. It's not the way you want your wedding day to go," Molaro says. It'll carry over into the following week when Leonard confronts Mandy, played by Melissa Tang. "He's doing all he can to clear the air. We don't shy away from it at all the first few episodes."

4. Break to breakup After not getting the space she had requested from Sheldon, Amy will sadly pull the plug on their relationship, which only flummoxes Sheldon more. "He is a man of science and he is being presented a problem of the heart that is not easily solved. Problems that are not easily solved by logic can be extremely frustrating for him. That's something new that he's gonna be dealing with," Molaro says. "He's having a lot of mixed feelings. He's mad at her, he wants her back, he's confused. There's a lot going on in his head and in any given scene, it can bounce back and forth."

Molaro, however, doesn't think either is at fault for the relationship's (temporary?) demise. Amy rightfully wants more, but in Sheldon's defense, he has also come a long way in five years. "I think she does love him, but it's an unorthodox relationship. I think she's not sure what she needs. She doesn't really have anything to compare it to and she's just trying to figure things out," he says. "From his point of view, it's 'Look at how far we've come in five years. We went from having no relationship to hand-holding to kissing to I love you.' And now, he was thinking about proposing. For him, it's flying by."

5. Single and ready to mingle? Neither Sheldon nor Amy will play the field, but they're definitely thinking about the other fish in the sea. "It's all wide open for them to date someone else," Molaro says. "While painful and confusing for both of them, I think as far as people go, I think it's a great growth opportunity for both of them, which could ultimately be good for whatever their relationship ends up being, if they're back together or just friends."

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6. Third-wheeling Poor Sheldon. Not only will he lose his girlfriend, but his roommate as well, now that Leonard and Penny are married. "The first main challenge is living arrangements and the Sheldon of it all. [Leonard] has to move out," Molaro says. "We've said half-jokingly over the last couple of seasons that it's kind of the three of them getting married and the three of them are a couple, and I think that continues on in certain ways."

Sheldon is not the only third wheel, of course. Howard (Simon Helberg) and Bernadette (Melissa Rauch) are still stuck with Stuart (Kevin Sussman) after feeling bad about asking him to move out on his birthday. "He's something of a pet for them at this point. Weirdly, I think they're finding a point where it's fine. Fine is a strong word. It's OK for now," Molaro says. "We behind the show love Kevin. It's perfect excuse to keep him around." So how about keeping him around as Sheldon's new roommate? "Could you imagine? We do have thoughts about bringing him [in with] Sheldon, but no immediate plans. That would be a lot of fun."

7. Just can't quit you Instead of dumping the super macabre Emily (Laura Spencer) last season, Raj (Kunal Nayyar) did the opposite and told her he loves her. Unfortunately, he still doesn't have the balls to cut the cord. "He can't do it. He wants to, but he can't. He's a little too insecure!" Molaro says. "It's tough for a guy like him who doesn't really know how to be in relationships and is also afraid of being alone. He's just stuck right now." So, is he trying to force himself to like Emily at least? "Possibly. Laura will be back. Maybe it'll turn into a true opposites-attract thing."

8. What's in a name? Bad news for those of you hoping to learn Penny's last name during the wedding ceremony. "I think some things are best left unsaid as mysteries of the universe forever," Molaro quips. "There are thoughtfully placed reasons how that works itself out where you don't hear it and you will see that. I think we covered our bases well. And now her last name is Hofstadter!"

The Big Bang Theory returns Monday at 8/7c on CBS.

(Full disclosure: TVGuide.com is owned by CBS.)