Our Gemara on Amud Aleph discusses an opinion that even though the Sotah ritual is activated by the husband according to a formula prescribed by the Torah, this act of jealously warning her to not to be alone with a certain suspected person is forbidden, because it causes strife (see Rashi). 

Shitta Mekubetzes raises an obvious logical objection. If it turns out that he legitimately suspects his wife of immoral behavior, and he is not just being paranoid and suspicious, why should it be forbidden? Isn’t it a good thing to warn her and to try to correct her behavior? The Shitta gives a remarkable answer. He says, this opinion follows the opinion discussed in Gittin (90a) that it is permitted to get divorced even over domestic and emotional concerns, as opposed to actual infidelity. Therefore, since it is permitted to get divorced, why cause strife? If he really suspects her and he cannot work it out with her, he should simply divorce her. On the other hand, according to the opinion of Bais Shammai, it is not permitted to get divorced, except if there is strong evidence of infidelity. Therefore the opinion in our Gemara that kinuy “warning” her is allowed even though it might cause strife, is because there really isn’t any other choice as he cannot divorce her without evidence of infidelity. Therefore, he must resolve the issue within the marriage by using the warning and ritual.

This reminds me of something that I often repeat to people who are in conflict laden marriages. Divorce is a serious step  that can bring anguish and trauma, especially when there are children involved, it is still technically permitted. However, ona’as devarim, hurtful and mean speech is a Biblical prohibition (Bava Metzi’a 58b). So if you cannot manage to work out your issues, it is a greater sin to stay married, and hurt the other person continuously, than to just simply divorce and move on.

By the way, it actually is not a clear-cut issue at all whether or not divorce is permitted. See, for example Shulkhan Arukh EH 119:3 and Arukh Hashulkhan 119:8. On a practical level, it is highly discouraged, although technically might be considered permitted in our day and age where divorce is by mutual consent (see Rama ibid). Nonetheless, even those poskim who come out on the side of strongly discouraging divorce, or even forbidding divorce, I have little doubt that they would consider it to be a worse sin to constantly violate the biblical prohibition of ona’as devarim over years and years of dysfunctional, high conflict marriage.

The bottom line is, working on a marriage is vitally important. But if you are unable to do it right, for whatever reasons and challenges you experience in yourself or in your spouse, and you end up behaving cruelly to the other person, it certainly seems that it is much better to divorce and far less of a violation.