I can’t believe how many people on this show lie or withold truth from their partner, while spilling the whole tea in the one-on-one interviews with the producers. Like Sophie telling us, the viewing public, that she’s bi, before telling her fiancée. Or Jasmine revealing her whole “plan,” etc. There are so many examples of people communicating way better in the one on one interviews than they do with their own partner.
Casting agents have openly said that learning that one partner is keeping a secret is more likely to get them cast. I’m sure it’s a direct question when they’re interviewing potential couples (they probably interview them together and then individually).
Also, a lot of the “secrets” are things that probably just wouldn’t be discussed if not for cameras rolling and needing a big reveal. A good example is Rebecca’s not-yet-finalized divorce- she probably didn’t NEED to tell Zied that; he likely didn’t understand US divorce procedures and it’s not like she was still living with or hanging out with her ex.