The marriage bond is sacred, and it should not be dissolved while both spouses are alive. I personally believe that divorce is always the result of sin. The Bible permits Christians to divorce if the other spouse has committed a horrible sin such as adultery (Matthew 19:9). If you divorce your spouse for smaller reasons, it is you who are committing the great sin, since you are giving up on your life partner before they have given up on you. You are proving that you were a liar when you vowed before God and witnesses that you really loved that person.
Christians are not permitted to divorce their spouses simply because their spouses are not believers. We must remain committed to our marriage partners even if they do not believe in Jesus Christ. We might not be able to stop our partner from divorcing us, but we should not be the ones initiating the divorce:
To the rest I say this (I, not the Lord): If any brother has a wife who is not a believer and she is willing to live with him, he must not divorce her. 13 And if a woman has a husband who is not a believer and he is willing to live with her, she must not divorce him. (I Corinthians 7:12-13 NIV).
Unfortunately too many people want out of their marriages. They try to come up with some justification when they have no good reason. I think this is because people are selfish; they want out of the marriage because they feel that the marriage is no longer benefitting them. They want “better” sex or more money, and so they selfishly try to dissolve the sacred bond with a partner who has stood by them so many times. But Christians ought not to behave this way. Rather than looking for a way out of marriage, we need to be constantly looking for a way to serve in marriage, even if our spouse is an unbeliever. We bring shame to the name “Christian” when we abuse our marriages selfishly for our own interests. Christianity is about sacrificial love, and so is marriage. It is time that more Christians started living this out.