In loving somebody, you realize your own shortcomings. And in loving that person, you want to become someone better for them.
You become a better person by curtailing urges, impulses, and addictions with self-control. By trading in your selfish “it’s all about me” mentality for one that includes the word “us.” That means thinking beyond yourself and immediate gratification.
At some point, we realize our vices are hollow pursuits, and instead spend our time and energy on those pursuits with purpose – like earning an honest living to support our families, pursuing the hobbies that balance us out and make us happy.
It is a sacrifice: it requires you to say “no” to what you’ve been saying “yes” to: whether it be drinking, drugs, gambling, pornography – whatever your weakness is. It requires losing touch with friends that encourage those empty pursuits.
But although it’s not easy, soon enough, you will find joy in other pleasures. And these ones won’t be empty.