Mere good sex doesn't secure a man — otherwise most prostitutes would be engaged. What secures a man is how you treat him.
Every man needs her woman, especially in the difficult hours of his life. Just like in a chess game, the queen always protects the king. A good woman is that woman who chooses a man with potential and, either sets him on a straight line, or stands by him as he does what he needs to overcome his troubles — silencing everyone who didn't have faith in him.
Far too many people (men and women) exist today who complain about "bad men", but there's scant few who work to create that difference they'd like to see.