A couple questions come to mind right away.
Are you the same sex and just friends? If the answer is yes, then the Soldier needs to check his housing contract about having permanent guests living in the quarters with them. From my experience, there is a clause in most housing contracts that prevents this. There are exceptions for family members visiting for a lengthy period of time. From a UCMJ standpoint, there is nothing wrong with this. However, you would still be required to maintain your room in the barracks.
If you are not the same sex I would highly discourage this idea. Assuming that you are not romantically involved, the fact that you are living there could present a perception of an inappropriate relationship regardless of your ranks.
If you are romantically involved, then you and the Soldier should be aware, that you both could potentially be charged with adultery under the UCMJ. Even though the Soldier is going through a divorce, it is still a violation of Article 134, UCMJ for that Soldier to have sexual relations with anyone who is not their spouse. Also, a single Soldier who has sexual relations with another person while knowing that person is married can be charged with adultery. Stay away from this situation until the Soldier’s divorce is finalized.