Can Divorced Christians Remarry?

Can a Christian, who has had a valid reason for divorce, remarry?

I believe the answer is 'no'.

"Aha!" one might say to me after citing Matthew 19:9 ("I tell you that anyone who divorces his wife, except for sexual immorality, and marries another woman commits adultery"), "Doesn't it say here that if your spouse has committed adultery, and that you have separated from your cheating spouse due to this, that you are allowed to remarry?"

One might add, "It seems unfair if you are not allowed to remmary, since it is your spouse's fault."
Admittedly, this verse may be construed as provision for remarriage following separation from an unfaithful partner. However, such a perspective would not be congruent with what the early church taught.

In the Shephard of Hermas (a Christian literary work of the 2nd century that is considered a valuable book by many Christians, and considered canonical scripture by some of the early Church fathers, such as Irenaeus), we find Hermas questioning his heavenly guardian about what a man should do if he learns that his wife is guilty of adultery and persists in it:

"I say to him, 'Sir, permit me to ask thee a few more questions.' 'Say on,' saith he. 'Sir,' say I, 'if a man who has a wife that is faithful in the Lord detect her in adultery, doth the husband sin in living with her?' 'So long as he is ignorant,' saith he, 'he sinneth not; but if the husband know of her sin, and the wife repent not, but continue in her fornication, and her husband live with her, he makes himself responsible for her sin and an accomplice in her adultery.' 'What then, Sir,' say I, 'shall the husband do, if the wife continue in this case?' 'Let him divorce her,' saith he, 'and let the husband abide alone: but if after divorcing his wife he shall marry another, he likewise committeth adultery.' 'If then, Sir,' say I, 'after the wife is divorced, she repent and desire to return to her own husband, shall she not be received?' 'Certainly,' saith he, 'if the husband receiveth her not, he sinneth and bringeth great sin upon himself; ... For this cause ye were enjoined to remain single, whether husband or wife; for in such cases repentance is possible.'"

Here, it should be noted that Hermas allowed for separation because of adultery, but required that the man remain single in hopes of his wife's future repentance.