"Lewis said that you don’t get married to become happy, but rather to make the other person happy. Your own happiness is a by-product, a consequence, of maintaining the proper end. If, by contrast, you get married simply in order to make yourself happy, your true happiness is made that much more unlikely."
Let that sink in. That's the formula. If we are constantly thinking, I wish I was happier in my marriage, we are actually wasting precious time and energy keeping us from what will make us truly happy. The more we seek to make our life happier for our spouse, the happier we will become in the process. But its an act of surrender, we can't look to control how our spouse will receive our kindness. Just love and let God, who is mysteriously present within the Sacrament of marriage, do all the work. That is what is so interesting about the Sacrament of marriage, the Grace is life long, and the grace is always present. I believe it was GK Chesterton that joked, the reason that marriage is a sacrament, is because we need it to be, or else a man and a women could never co-exist for life! But with the Sacrament of marriage, not only can a man and a women co-exist, but we can thrive!