An orgasm is a neuro muscular discharge. The book is talking about prolonging high levels of pleasure. Nature has limits, as does your body. You can learn from the book but you won't be thrashing about for an hour. Sure there is too much sex.
Some people have as many as a thousand partners a year.
After that many partners, sex would be as common as breathing, and would lose all meaning. Telling a possessive and angry husband might be a risky thing to do. You might need a priest or a friend to be a mediator. There is a female condom but it is a very odd contraption. Nobody seems to like it.