"Married at First Sight" season 4 has only just begun, but the clock is ticking and there are already rumors about the struggles that each couple will have to bear. The upcoming fourth and fifth episodes will see the three pairs deal with the ups and downs of a newly established relationship.

For those who are unfamiliar, "Married at First Sight" features three pairs of strangers who are wed the first time they meet. The fourth episode, titled "Just Married," will apparently see the couples talking to a relationship expert before dashing off to their honeymoon destinations. Sonia and Nick will talk about their personal insecurities, Heather and Derek will discover something about each other, and Tom and Lillian deal with a secret. The episode airs tonight.

The fifth episode, titled "Honeymoon, Pt. 1," will see the couples jet off to the Caribbean to spend some time alone together. The three pairs will find themselves in Jamaica, learning more about each other. The synopsis also points out that issues will arise between Heather and Derek. Although the summary doesn't explicitly state it, the issue could have something to do with the latter's smoking problem.

Derek is an avid smoker of pot and, even though the Heather seems fine with it at first, it soon becomes clear that it gets on her nerves. In fact, the problem will be too huge to avoid and it will eventually bubble up into something that separates the two.

According to In Touch Weekly, Derek and Heather won't even last until "decision day," effectively ending their relationship before the finale. "Heather refused to put up with his smoking," the source told the publication. "Heather and Derek's relationship was very short lived."

With Derek and Heather out of the running, it's down to the two couples still holding on. Tune in to "Married at First Sight" season 4, which airs every Tuesday at 8:30/7:30c on FYI.