Can one combine a new marriage with patience towards the current wife to address marital unhappiness resulting from the wife's obesity, while considering the interests of religion, oneself, and the family?

Obesity is a treatable disease, so it is better to be patient and help your wife seek treatment. If her treatment proves impossible, and if you are able to marry a second wife and overcome your apprehension that this would not cause problems, then it is better to keep her as your wife and marry another, provided you uphold justice. If there is no alternative but to separate from her and marry a second wife, then do so, for Allah will enrich each of you from His bounty, as He, the Almighty, says: "But if they separate [by divorce], Allah will enrich each of them from His abundance."