If there is any given fact about the human condition, it is infidelity, this goes back as far as we have records of marriage being a thing. The modern change is how we see marriage and relationships.

And while I agree on the friends make good relationship partners, it is not the duty, or even the point, of the other person "completing" you. If you want a good relationship, you need to be "complete" on your own, because no one, not even a romantic partner, can do that for you.

PS:

with twice as many being the mens’ fault, probably due to their own faults not being the men that women deserve

you're a "feminist" (bigot who hides behind the veil of equal rights for all sexes, note the massive quotes) aren't you? I would recommend you do some introspection if you really believe yourself a feminist, and why you would victim blame anyone for "not being good enough" real "you made me hit you" vibes here