Religion, certainly, carries ideas about marriage that many people share. As a person and an interfaith pastor, I encourage consciousness - ideally before marriage, but bringing it in at any time is valuable. What commitment is healthy for you?
I do not believe that happiness is a key measure of what to do in life. Of course, happiness is, in a sense, the purpose of everything. But we can learn that happiness does not depend on our external situation. My wife and I initially chose "till death do us part." We went through many difficult years, but not because of that, simply because we were still deeply in love, and had never learned to get along. Part of love is learning to be happy together. And any one day of my marriage now is worth the 30 years of pain it took to get here. (And it wasn't all pain along the way.)
I encourage clear thinking. What acts are a basis for divorce? Spouse or child abuse? Imprisonment? Inability to live one's spiritual practice or life purpose while sharing a life with the other? Infidelity?
In today's multicultural world, we are informed by religious views, but we are only guided by religion if we choose to be. And we live with the consequences of our actions.
What brings the deepest level of unconditional happiness, love, and wisdom? Can you live your life purpose and continue your marriage? These, I think, are more important than conditional happiness.