Don't let someone else's unnatural behavior become your problem. You weren't made to feel depressed or unhappy because of what others do. You were made to be happy with them. If someone is miserable, remember that their misery is their own fault. God made everyone to be happy and free from worry. He gave us the tools for this. Some things belong to each person. Other things don't belong to them. Some things can be blocked, forced, or taken away — these don't truly belong to anyone. But the things that can't be hindered — those belong to you. And your understanding of good and evil? God made that yours too. He did this because he cares for us and protects us like a father.
Let not that which in another is contrary to nature be an evil to you; for you are not formed by nature to be depressed with others nor to be unhappy with others, but to be happy with them. If a man is unhappy, remember that his unhappiness is his own fault; for God has made all men to be happy, to be free from perturbations. For this purpose he has given means to them, some things to each person as his own, and other things not as his own; some things subject to hindrance and compulsion and deprivation; and these things are not a man's own; but the things which are not subject to hindrances, are his own; and the nature of good and evil, as it was fit to be done by him who takes care of us and protects us like a father, he has made our own.