There’s a team of experts on their side. Married at First Sight‘s long-time sociologist, Dr. Pepper Schwartz, opens up to The Knot in an exclusive interview about the season 4 couples, who appear to have encountered major relationship roadblocks early into their marriages. Dr. Pepper, who takes an empathetic and compassionate approach to offering marriage advice to the FYI couples, says she believes one rocky couple still has a shot.
Derek Schwartz and Heather Seidel began arguing just days into the six-week experiment. While honeymooning in Puerto Rico, Heather was turned off by her husband’s smoking habit. One altercation led to a series of heated arguments, and when they returned from their honeymoon, Heather decided she needed time alone to decide whether she wanted to continue the marriage. The flight attendant ultimately made the difficult decision to break things off with Derek.
Once the dust had settled, Dr. Pepper stopped by Heather’s Miami apartment before meeting with Derek separately. It was clear that the expert wanted a better understanding of what had gone wrong in the couple’s marriage. Now, it’s abundantly obvious that Dr. Pepper can see both points of view.
“I think there were some difficulties that a less moralistic person than Heather could perhaps have gotten past,” the Married at First Sight expert tells The Knot exclusively. “Heather felt her moral code had been trespassed by what she thought was addictive behavior — the smoking. Derek had poor judgement smoking so much so soon when it was clearly something she was uncomfortable with, even if she said it was OK to begin with.”
“I really feel for both of them,” Dr. Pepper openly admits. “Heather was not attracted to Derek after that experience, and it’s no fun to try and warm up to someone who has crossed some moral and behavioral boundaries.”

Photo by Kinetic Content
The expert acknowledges that Derek didn’t get the experience he was promised. “He wanted to talk to the experts, to grow, to get to understand his wife, and none of that was going to go forward,” Dr. Pepper tells us. “He apologized, but ultimately it is fair to say she had decided he was never going to be her type and it was over for her.”
The fact that the couple’s relationship would be televised most-likely made Heather’s decision an increasingly difficult one. “She knew it would make her unpopular, but she also felt pretending was wrong,” Dr. Pepper explains. “She felt as though she was between a rock and a hard place, and Derek felt he hadn’t been given a fair chance. In my opinion, no one was right or wrong in this situation.”
In a preview for the next Married at First Sight episode – airing Tuesday, September 27 – viewers learn that Derek and Heather meet face-to-face. While some fans may have hope that the couple will give their marriage a second chance, Dr. Pepper reveals there was a different reason for the meeting.
“I don’t think there was hope that they would rekindle their relationship,” she tells The Knot. “Instead, there was some need for closure and to make Derek feel somewhat less rejected and for Heather to be able to explain herself better.”
While Derek and Heather’s incompatibilities were clear early on, Nick Pendergrast and Sonia Granados‘ relationship troubles seemed resolvable in comparison. Nick wanted to build a friendship with Sonia before becoming physically intimate, and while Sonia was ready for intimacy, she was patient with her husband.
On the latest Married at First Sight episode, however, Nick grew increasingly irritable during a conversation with Sonia, finally admitting he doesn’t believe their marriage should take effort since they were scientifically matched. He then shocked his wife (and viewers!) when he shared that he doesn’t like Sonia and doesn’t find her attractive.
Dr. Pepper believes that Nick’s drinking played into the quarrel. “I think Nick’s rant was fueled by alcohol, fatigue and from being asked to articulate his feelings,” she explains. “I would advise everyone to avoid a serious conversation if drinking alcohol is involved.”
The sociologist tells The Knot that the Married at First Sight experts look for “a ratio of similarity and complementarity” when they match the participants. “We thought they would be sympathetic with each of their shyness about sharing things and could grow together,” she says of Nick and Sonia. “We thought that someone too gregarious would be hard for Nick and that Sonia might need someone a little more contained than gregarious because she can be more timid at times.”
The expert admits that both Nick and Sonia were “much more open” during interviews than they have been with each other. The fact that cameras were rolling may have played into the breakdown in communication.
“We saw Nick’s sincerity in wanting to do the experiment, and we also felt that he was far more affable with us than he was when pressed during the documentation,” Dr. Pepper explains. “Having a crew asking you to think very deeply about who you are and who the other person is, is very hard for some people – and I think it was especially hard on Nick.”
“I think Nick felt that Sonia was beautiful at the wedding, and I think he continued to find her attractive until he resented her questions,” the expert continues, “and that’s when he got mean and told her he didn’t find her attractive.”
Despite their issues, Nick and Sonia have compatible qualities as well. “There are many things about them that can make them very happy together. They can have a lot of fun together and admire a lot about each other,” Dr. Pepper shares with The Knot.
Viewers saw those compatibilities during Nick and Sonia’s honeymoon in the Dominican Republic. They share an adventurous and competitive nature, as well as a deep desire to be in a committed relationship – which made it even more shocking to see Nick’s darker side.
To help viewers understand why Nick may have made such hurtful remarks to – and about – his wife, Dr. Pepper acknowledges that he was angry and defensive, and a lot of people say “nasty things” when they reach that point.
“I don’t believe for one moment that Nick was not at all attracted to her or didn’t like her most of the time, but I think he was aggravated and lashed out inappropriately,” the expert asserts.
After Nick’s outburst, Sonia packed her suitcases and left the couple’s home. In the past, the Married at First Sight experts have cautioned the participants that leaving the situation is often not ideal.
“I never think it’s a good idea to leave an argument and leave the house, however I can understand that she was really hurt,” Dr. Pepper tells us. “He had been mean to her, and going back to bed with him that night would’ve felt awful… I don’t blame her for feeling discouraged and humiliated and wanting out of there, and I think she had to do that for her own dignity. However, that doesn’t mean she won’t come back or reconsider.”
It seems Dr. Pepper is hopeful Nick and Sonia will work out the kinks in their marriage. “I feel this couple needs a lot more tools about how to talk or not talk when they’re upset about something,” she shares. “Sonia needs to know when to give him space, and they have to figure out the right time where Nick can talk about his feelings in a positive and constructive way.”
Dr. Pepper tells us that the Married at First Sight experts comforted Sonia after Nick’s rant. She shares that they both needed time to “cool down and take a bigger picture look at their relationship and talk more together.”
The sociologist has advice for Nick and Sonia that could be helpful for any couple. She tells The Knot readers: “You have to pick your moments about when you can talk, regret what you’ve said, think about how you really feel, and find out why you said the things you said.”
The story continues on Married at First Sight, airing Tuesdays at 8 p.m. ET on FYI.