Jesus christ dude.

I put a check mark for today on the calendar I use to track my Quirrelmort-inspired cynicism.

But even though crime happens, that doesn't mean that everyone is a criminal.

Brains evolved to enable people to exploit dumber people.

It sounds to me like what might have happened in your case is that you focused really hard on being "good" and not so much on being "powerful"

I naively believed the best way to get a good wife was to act like a good husband.

It turns out that the best way to get a good wife is to be powerful...and the way to become powerful is to selfishly build up skills/power/experience, including sexual experience.

you live in a city that has a dog-eat-dog dating culture.

Welcome to any metropolitan city.

consider the possibility that the bad actors you were harmed by were themselves acting in aggression in response to some bad situation like growing up with an absent father

Probably. But what difference does it make? They still hurt me, violating norms of civil behavior, and were not (and cannot) be punished for it. Thus, the rational thing for me to do is to do unto others first.

Justice is a lie told by the powerful.

A person who's maximizing total utility is not going to grant every favor asked of them.

I am a "happiness monster". My utility deserves a 1000x multiplier.