How?

Earlier in the day my Dad and I were sent to gopher I guess you could say. We were doing things for others like we do a lot. I told him I was getting nervous, I don't want to not succeed. I am trying so hard, we both are, to do something for ourselves. 

I have been wondering, how? My Dad asked, "How have you not started drinking, having meaningless sex and doing drugs like smoking or marijuana."

I'm clueless. 

The only answers I come up with is that I don't have the temptation that someone gets. I don't want liver cancer from drinking, I don't want meaningless sex, it helps I don't ever see anyone outside my household. And I don't want lung cancer from smoking. 

It is really a mystery.