Bad relationships may increase your risk of heart disease.
Just out in the Archives of Internal Medicine:
A study of 9,011 British civil servants, most married, found that those with the worst close relationships were 34 percent more likely to have heart attacks or other heart trouble during 12 years of follow-up than those with good relationships. "Relationships" included that with partners, close relatives and friends.
What does it mean? Just more information suggesting that stress has a larger effect on one's general health that we previously assumed. Which makes intuitive sense, and people probably know/feel, but science has yet to catch up to this concept.
What to do? Easier said than done, but don't stay in bad relationships.
It's not worth risking your health.