For many couples, "til death do us part" conjures images of white-haired spouses holding the hands of their ailing life partners. But sometimes this idyllic picture is not how life turns out. When a spouse contracts a serious illness earlier in life, it can take a serious toll on the relationship. While the future is uncertain, the day-to-day routine of the family is affected greatly. Perhaps the sick person is in and out of the hospital, leaving the rest of the family members to do the things he or she once did. There may be financial strain if the sick spouse can't work anymore. And everyone in the household will have their own thoughts, fears and emotions to deal with. The patient may not want to express his or her emotions in order to keep the other partner from worrying more than he or she is already, and the well partner may bottle his or her feelings of sadness and fear to protect the patient. While some of this behavior is helpful – keeping a positive attitude is important – being dishonest about the way things are isn't the best approach. Negative feelings happen, and it's OK for everyone to address them in a caring way. Perhaps the caretaking spouse is resentful and overwhelmed. The sick spouse may feel guilt that he or she can't complete the responsibilities he or she once had.

Listening to one another's feelings and taking them day by day – not allowing resentment to build up – is the way to handle things. Ideally, couples will discuss the "what ifs" of a life-threatening situation beforehand, but if that's not the case, then it's OK to broach the subject early in the illness to ensure that things go smoothly, no matter the outcome of the illness. Practical issues to consider are child care, power of attorney should the patient be unable to articulate his or her wishes, financial obligations such as money set aside for any children's education, and so on. When a woman in a heterosexual relationship is the one to get sick, it's common for her male partner to feel uncomfortable and out of place as the new caretaker. A 2009 study in the journal Cancer cited a much higher divorce rate for couples in which the woman sustained a serious illness. However, the study found that women were more likely to stay in the marriage when the man was the sick spouse. Regardless of who is sick, it's important to stay united against the illness, not each other.