Divorce, at least for me, was a last resort. I will attempt to articulate clearly, why I feel that, sometimes, it is the only option.
Since I live my life as a Christian, I endeavor always to "walk the walk"; in order to please my Heavenly Father. Often, like everyone else, I miss the mark. Coming to this decision was indeed,a very painful and, at times, tormenting one. When the person you are yoked with; especially in marriage, is practicing and devising sin, your life, and that of your children, becomes a continual harvest of destruction.
There is a universal, spiritual law of sowing and reaping. Whether one is a Christian or not, this law is still operational. God's word is relevant and absolutely true. Personally, I cope with this decision, knowing that God does not intend for our lives to be a continual process of negative, unrelenting chaos, tragedy, and disaster. This is what my marriage, and I'm sure, others has been. I just woke up one morning and decided, "It's enough"! No more will my child and I pay for the poor decisions, and destructive behavior of someone who caters only to his or her flesh.
The real test of love, no matter what the nature of the relationship, is selflessness. Love is a word often thrown about, but seldom truly understood or honored. Love is an action, not a word. If there is no fruit, there is no love. When you truly love someone, with a Godly,appropriate love, you put their needs, dreams and desires, before your own. You let them go, and wish them well; that every good plan God has for them comes to pass, and no matter your own agenda, loving them enough to allow them their freedom.
There is not a short answer to this question, for any of us. And, when you are writer, words are your "paintbrush", so, I pray you enjoy and appreciate the "picture".