This was revealed when they came back for the reunion episode. During this episode, Derek revealed that he learned that Katie had been having an affair with her ex-boyfriend after Decision Day, and he thinks that she may have been having an affair with him even before Decision Day.
Married at First Sight Spoilers- Derek Sherman Does Not Want to Appear Back On MAFS
Recently, Jamie Otis asked Derek if he was willing to go back on the reality show when he appeared on Jamie and Doug Hehner’s Hot Marriage Cool Parents podcast. In response, Derek said, “Oof, I do not regret getting married at first sight for a second. From what I’ve gained from this, just about myself and the friends I’ve made throughout it, made it all worth it.”
He continued by saying, “But I don’t know if I would do it again, because it was just too taxing. You really don’t know what you’re getting yourself into. After I’ve been through this, I’m going to have to say, ‘No.’ I don’t think I would do this again just because it is actually pretty hard, because you have your whole life in front of the world.”
Married at First Sight Spoilers- How Derek Sherman’s Relationship with Katie will Affect Future Relationships
He would go on to say that being on the show was a great experience but that he would not be able to make a living off of it. He would go on to say that Katie’s affair has not made a negative impact on how he views marriage. He stated, “So, I mean, once it happened, it pretty much just closed the door on anything Kate and I had. So that’s how I viewed it in regards to our marriage, but I haven’t taken it outside of that at all.
So going forward for me, that was just something that happened in the past, and I’m not going to weigh that going into the future. I’m not going to be more insecure about the person I’m seeing and whether she’s cheating or not. I’m an advocate — it’s just who I am in general — that I’ll blindly give you trust until you do something to make me lose trust in you, and that’s kind of how I see things.”
Doug went on to explain, “I feel like you learned a lot from the show and you’re taking away some great lessons and you’re really a great individual… Not everybody can handle it the way you have, and to take the positive out of things is not something that everybody can do. But it’s not slowing you down; it’s giving you some drive. And you sound extremely happy.”