Your heart naturally gravitates to what you focus on. If your attention goes to a certain car model, your heart goes to it. From there, your heart will order your mind to obtain it. Then, given enough time and effort, you will have the car.

Jesus explains it like this:

For where your treasure is, there your heart will be also. (Matthew 6:21)

So, if you stop focusing on your marriage, your heart will leave your marriage. Then the feelings of love for your partner will lessen. And the end of your relationship is only a matter of time. But if you don’t you understand what is going on, you will think our “love died.” But in truth, it didn’t finish. You starved it, left it malnourished and mistreated when you stopped focusing on it.

Want to get your love back? Focus on your marriage.
Want to multiply your money? Focus on how money functions.
Do you want wisdom to get what you want? Focus on God.

What has your attention, has your heart. What has your heart, controls your attitudes.