Should the military ban marital infidelity?

On June 2nd, 2013, you answered the question: "Should marital infidelity be illegal?" I agree with you that infidelity shouldn't be illegal. However, might some government organizations -- such as the military -- legitimately ban and even criminalize infidelity for its voluntary members? According to the Uniform Code of Military Justice, infidelity is against the law for military members. Might that be proper? Might the military want to enforce strict rules of moral conduct on their members, even for seemingly private matters?