We cannot blithely accept no-fault divorce (in which we are too often willing participants), for example, and then complain that Obergefell redefined marriage. (Carl R. Trueman, The Rise and Triumph of the Modern Self: Cultural Amnesia, Expressive Individualism, and the Road to Sexual Freedom, pp. 389-90)
Just as liberal theology was present prior to rank apostasy, so likewise the seeds of destruction of family and sexuality were planted prior to the embrace of "homosexual marraiges." In this one sentence, Trueman rightly pointed out one major way in which many professing Christians have already compromised on the topic of sexuality - that of no-fault divorce. I would like to venture further than Trueman here though. Christians who have compromised on the issue of divorce by allowing for divorce on reasons others than what God allows, and churches that allow for such divorces, are complicit in evil and plant the seeds of destruction in their lives, churches, and societies.
God is very clear on marriage as the union of one man and one woman for life. In unambiguous terms, Jesus in Matthew 19:1-12 states what marriage is and, alongside Romans 7:1-3, gives the only reasons for divorce. Divorce is only permitted upon adultery and desertion amounting to death. Abuse is not mentioned in the Bible, even though many husbands in biblical times have abused their wives. Thus, abuse can only be legitimate if is reaches the level of desertion, and that's all. All the other reasons normally given for divorce (non-reconciliable disagreement, unable to trust etc.) are NOT legitimate reasons for biblical divorce, ever.
In response to Jesus' teaching, we must remember the disciples' astonishment as they exclaimed, "If such is the case of a man with his wife, it is better not to marry" (v. 10). Now, if Jesus did in fact allow for divorce because of those other reasons, the disciples would not have been startled by Jesus' teaching, would they? But the disciples clearly understood how strict Jesus' teaching was on divorce, where basically only extreme sins against the marital bond would break it.
In this light, it is a sad reality that professing Evangelicals do not abide by Jesus' teachings on the matter. And even when the church formally teaches it, it is not practised and enforced. Whether a churche truly believes in biblical marriage and divorce is not seen in her teaching on the matter but on whether she actually acts on those teachings. If a professing Christian couple in the church divorces for unbiblical reasons, the church must put them under church discipline until they either repent, or they are excommunicated (c.f. 1 Cor. 5:1-5, 9-13). To not do so because of other reasons that the Scriptures do not sanction is to violate Scripture. And where appeal is made to their supposed contrition, that church has caved into the therapeutic mentality that saturates modern culture instead of following what Scripture commands. A truly contrite person will repent of his or her sins, and turn back to what God has commanded in Scripture. The idea that one can be "contrite" yet continue in disobedience to God is a contradiction in terms (c.f. Jas 2:14-26). And lastly, to resort to the "Gospel" as a way to excuse sin is basically licentiousness, and woe to those who misuse the grace of God to tolerate wickedness (Gal. 5:13-14; Mt. 6:23).
Judgment begins at the house of God (1 Pet. 4:17). As the sexual revolution destroys the world, let us move fast in the opposite direction. Christians are to not just reject sexual deviancy, but also to reject unbiblical notions of marriage. As the darkness grows, our lights need to shine brighter, and show people the way to the truth and the life.