Please just knock off the amateur psychiatry. Human beings aren't naturally wired to be monogamous[1]; that's why cultures have to exert tons of social pressure on people to be monogamous. Wanting to have sex with people who aren't your partner doesn't mean something's wrong; it's the natural state of the human being. A lot of people repress this with tons of social pressure and denial, but it's still there for probably a lot of people.
If you're one of those people, I think acknowledging it and choosing to avoid temptation for the sake of accommodating a partner is, if anything, even more loving than living in denial.
[1] If you doubt me, you can start with all the literature about sperm competition in humans, or about the high incidence of adultery.
The belief that others' cognitive processes are essentially similar to one's own is called projection bias, BTW.
I'm interpreting your comments as straightforwardly as I can.
In the general case, though, it's a dick move to criticize the merits of a complete stranger's marriage. The exact substance of your criticism is a comparatively minor issue.
After a bad first experience I put off marrying again for a long time. When I did marry again, it was we were past those kind of trust questions. It's neither perfect nor predictable, but nor does it feel like a trade-off.