This is news to me. It must be relying on superceded old law.
Colorado's Dissolution of Marriage Act provides that "All issues raised by these proceedings shall be resolved by the court sitting without a jury." Section 14-10-107(6), Colorado Revised Statutes. Recent case law is in agreement: "All issues raised or presented in a dissolution proceeding are to be resolved by the court in equity sitting without a jury." In re Marriage of Lewis, 66 P.3d 204, 205 (Colo. App. 2003).
One can image a case where the existence of a marriage was an issue in a non-divorce case and this was resolved by a jury (e.g. a criminal trial for statutory rape), but that is an entirely different idea.
Footnote On Non-Divorce Claims In Divorces
The Lewis case, indeed, goes even further. It states that non-divorce related disputes can't be included in a divorce case precisely because it would create a right to a jury trial:
The joinder of marriage dissolution actions with claims sounding in tort or, for instance, contract would require our trial courts to address many extraneous issues, including trial by jury, and the difference between the "amicable settlement of disputes that have arisen between parties to a marriage," and the adversarial nature of other types of civil cases. Moreover, such would create tension between the acceptance of contingent fees in tort claims and our strong and longstanding public policy against contingent fees in domestic cases. We conclude that sound policy considerations preclude either permissive or compulsory joinder of interspousal tort claims, or non-related contract claims, with dissolution of marriage proceedings.
Id. at 206.
The reasoning in the Lewis case quoted above is a bit off, however, although its conclusion that there is never a right to a jury trial in divorce cases in Colorado remains solid. Also, Lewis does not impact appear the rule that says that co-ownership of property that is the subject of a divorce that involve third parties (a kind of lawsuit which in some circumstances might include a right to a jury trial ordinarily) can be resolved in a divorce.
Colorado takes the position that the right to a jury trial is addressed on a lawsuit by lawsuit basis, rather than individually on a claim by claim basis. If the principal relief sought in the complaint is one for which there is no jury trial right, then there is no right to a jury in the case, even if other claims asserted in the case could normally be tried before juries or the defendant has a counterclaim that would normally be tried before a jury.
This comes up, for example, in mechanic's lien cases, where lawsuits to enforce lien rights don't have a jury trial right associated with them, even though breach of contract suits do. In Colorado, the mechanic's lien enforcement is viewed as predominanting over the contract suit, so there is no right to a jury trial in a mechanic's lien case, even on the contract claims asserted in the lawsuit.
Thus, Colorado has a race to the courthouse rule on jury trial rights, since counterclaims must ordinarily be brought in the same suit in which one is sued, or they will be considered waived. (The general rule that counterclaims be filed in any pending current lawsuit between to parties, or never when parties are in a lawsuit against each other does not apply to divorce actions in Colorado. Simmons v. Simmons, 773 P.2d 602, 605 (Colo. App. 1988).)
So, even if a tort of contract case were allowed to be joined to a divorce case, it isn't at all obvious that they would include a jury trial right in that context, because the divorce would still be the prinicipal relief sought in the case.