You are barring yourself from submitting to human nature.
What exactly is "human nature"? And how could that be recognized?
Humans are naturally violent.
Sure, sometimes.
But not always.
But the point is, you may often be tempted to do something against your morals, and it may frustrate you, but after getting past it you'll be glad you held to your morals.
You contradict yourself.
You said earlier -
Which seems to suggest that all that is necessary for happiness is to submit to human nature, instead of maintaining morals that go against that nature.You are barring yourself from submitting to human nature.
If human nature is indeed violent, then such qualms about what is moral and what isn't wouldn't exist or matter, no?