All the studies I have read make a point of how crucial having a social support like family/loved ones is to health. Just read another in regards to Alzheimer's in "Scientific American" yesterday.
No one is meant to be 100 percent self reliant and happy without the meaningful company of others. I maintain that a good SO is crucial to many aspects of health and this can be confirmed by many current articles and studies. Those who have healthy relationships live the longest and often the healthiest.