What percentage of marriages lead to divorce/sexlessness/unhappiness or cheating without the other knowing?

We've all heard "50% divorce rate" but when you include people staying married for the kids/financial reasons, sexless marriages, people that stay but are neutral feeling-unhappy in the marriage, or possibly get cheated on without knowing (I've heard upwards of 30%) -- what percentage of marriages do you think are a net positive for each person involved?

40%? 20%? 10%?

It's kinda wild how so many people live their lives (15-40) working up to marriage being the biggest event of their existence yet it has such low odds of actually being a positive experience. 99% all go in with the same hopefulness that they've "found their one and only person".