1. I'm not sure exactly why the military needs to "handle" anything related to marriage at all. 2. Immigration cases can be treated on a case-by-case basis without any regard for "marriage" under the law. Whether two people are immigrating as a "married couple" or as two individual adults doesn't necessarily make much of a difference, does it? Goofy and silly, you don't think that the military has to deal with marriage and families?
You think that immigration doesn't need to deal with married people and families?
The military only has to deal with families because we have a large standing military that has no place in the U.S. Constitution. There would be no need for any military involvement in families with true "citizen-soldiers" serving as the backbone of our military.
And for immigrants, the only question relates to preferential treatment of married couples under immigration law. Eliminate that provision -- along with all the "anchor baby" nonsense -- and the whole issue goes away.