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Big changes are coming to "The Big Bang Theory!" Warning: Spoilers ahead!

In tonight's season eight finale, relationships are going to be placed under the microscope and questions will be confronted when Sheldon (Jim Parsons) causes everyone to examine the progression of the couples.

To get the scoop on the good, the bad, and what's next for your favorite "Big Bang" relationships, ETonline called up executive producer Steven Molaro and he revealed that there are some "life-changing decisions" headed our way in tonight's final episode.

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ETonline: What can you tease about Thursday's season eight finale?
Steven Molaro: There's a lot of relationships going on in the show right now and I think we shine a light on most of them with some really, really big life-changing decisions being made.

ETonline: Does that mean that Penny and Leonard might finally set the date for their wedding?
Molaro: They are under a lot pressure in the season finale over the fact that they don’t have a date. What's interesting about this season finale is it also happens to be the fifth anniversary of the first time Sheldon and Amy met. So [Sheldon] is feeling pressure from her about the glacial pace at which their relationship is continuing and so he is asking uncomfortable questions to Leonard and Penny. If they're an example of a relationship that’s moving forward, why have they been engaged for over a year and don’t even have a wedding date? And I think he unintentionally gets them asking themselves honestly the same questions.

ETonline: Since Penny and Leonard are going to be facing the unanswered questions of their relationship, is someone going to start getting cold feet?
Molaro: I think you will find out a lot of really interesting things in the course of this episode, and I think it turns out it may actually be both of them. They come to some really big decisions.

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ETonline: Does this mean this is Sheldon and Amy's five-year anniversary of the "tepid water, please" date at the coffee shop?
Molaro: Yes! Boy, you know the show! That is exactly correct. [Laughs] Yes hard to believe it's been five years from that moment.

ETonline: So does this mean we can expect to see a big step in Sheldon and Amy's relationship?
Molaro: It's hard to say. You can't help but feel for Amy. She certainly puts up with a lot, but at the same time when Sheldon argues it is moving forward, he's not wrong. You could also make the argument that they have the most stable relationship on the show. If you were to plot [their relationship] on a graph, it is seemingly slow, but it is moving from point A to point B fairly consistently -- maybe even more so than the other characters. I have a lot of feelings about all the relationships on the show and ultimately want them to work out, but relationships can be tough.

ETonline: You're not going to break up any of our 'Big Bang Theory' couples are you, Steve?
Molaro: I think you need to tune in and see what happens. I'm really happy with how the finale has been going. We shoot it tonight, we shot parts of it yesterday, and it has just been really satisfying, and shocking, and amazing to get to watch these actors do what they do. They're just all remarkable.

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ETonline: What is the one thing you want 'Big Bang Theory' fans to know before tuning into the season finale?
Molaro:Really big decisions are confronted head-on and I think everyone will be surprised and pleased or shocked with a number of the outcomes. I think you're going to have a range of emotions like I did. I still end up watching this all play out ultimately as a fan of it, and a number of distant emotions are hopefully going to be triggered in you.

"The Big Bang Theory's" season finale airs tonight on CBS.

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