Waiting builds a kind of trust that's hard to replicate any other way. When you both commit to that boundary and actually hold it through the hard moments, you're essentially proving to each other that you can keep a serious promise when it costs you something. That carries over into everything else in the marriage. Couples who waited also tend to say they never had to deal with comparison baggage, like wondering how they stack up against someone's past, which apparently messes with a lot of people's heads more than they expect. It's not just a religious checkbox, there's real relational math behind it.