I read a thread from a couple days ago talking about alpha-beta hierarchy. The OP discussed an experience where a man was trying to rattle his confidence and when another user explained that this is how wolves operate, the OP said "we are not animals".

Newsflash, humans are animals. When considering all qualities combined, humans are the best animals. However, we are as much slaves to our biology as ants are. Acknowledging this fact has helped me develop a DGAF attitude and it could do the same for you.

Morals are BS. When a lion kills a deer and feeds on it, he doesn't feel guilt. We don't look at that lion and think what a shitty lion he is, if anything we admire it for doing it's thing. Just like a lion, a human eats, shits, and fucks. Why should you expect anything different?

Men love women. Women go for the top 10 % of men. Knowing these two facts, how can you be surprised that a man is willing to screw you over to get a hot piece of ass? An animal looks out for his/her own interest. If a stranger at the gym sees you flirting with a girl that he also wants to bone, he is not being immoral by trying to get you rattled.

Never expect anyone to behave "morally", especially a stranger at the gym. Male lions will kill other males and their offspring, just to breed with their female. Men are competitive, we are not all friends. Most men will care far more about getting hot pussy than you, this is nature. Accept it.

If a woman finds a man she likes better than you, she will drop you in an instant. Does it matter if you sacrificed a lot for her? Nope, humans are animals and will always behave like animals. It's her nature to branch-swing. It's your fault for getting attached and committing to a single woman instead of spinning plates, you tried to defy humans' animal nature and you will look, and a feel like a fool.

TLDR: Humans are animals, never expect morality from anyone. Access your animal nature and act accordingly.