I understand the argument a little bit, because essentially it argues for will power and the ability to accomplish things together. But you can do that with so many other things. I also understand the "He has the character to respect me" thing too, because you want a guy who will be interested in what you want and will do his best to uphold it. 

However, there are plenty of people in the world who have happy marriages who lived together and didn't wait and built a perfectly healthy, trustful marriage together. Just because you do have sex before marriage doesn't mean you automatically have no trust. The two are not mutually exclusive.