Watch Married at First Sight's Jonathan Go "Below the Belt" About Molly's Past Threesome

Marriages are full of ups and downs and the couples from Married at First Sight are no exception.

As Molly Duff and Jonathan Francetic continue Lifetime's experiment, the commercial insurance adjuster and Army veteran aren't seeing eye-to-eye on one important issue.

In an exclusive sneak peek at tonight's all-new episode, Jonathan begins to express concerns about not being intimate with his wife.

"I mean it's hard not to feel a little offended when Molly talks about instant chemistry, especially when she's already told me about the time she walked into a random frat guy in a bar and asked him to have a threesome and she didn't even know him," he shared. "At some point when you look at me and go, 'Yah, you're attractive' but I went and f--ked this Pike with my friend and I won't touch you and you sleep next to me, how do you think that makes me feel?"

Maybe this wasn't the best topic to bring up in bed…

"Okay, you going below the belt and bringing up college s--t. How f--king dare you! Go f--k yourself. Don't try to do that," Molly shouted. "I'm sorry I've had partners in my past and people I thought were attractive. What the f--k? So have you. The fact that you went there? I'm so f--king done."

Ultimately, Jonathan wants more of an explanation. Will he get it during this heated conversation? You have to watch and find out!

"I don't think you've ever checked into this marriage. That's the problem," he shared. "I want to make this work but I don't know how to fix this. Marriage is what I really want so if this doesn't work out, I'm going to be devastated."

Married at First Sight (produced by Kinetic Content) airs Tuesday nights at 9 p.m. only on Lifetime.