Don't Get Lost in Transition

One of you gets sick.

When one spouse becomes seriously ill, both suffer, says Córdova. The healthy partner is obviously worried about the other, and is likely dealing with practical issues such as insurance and medical bills. But there's also the fact that he or she is missing out on the intimacy and support they once got from their spouse. "If that person falls too far into the caretaker role, the dynamic between the couple shifts, which can be dangerous," says Córdova.

If you're in the caretaker role, then don't hide your feelings. "If one of you is suffering, the other likely is too," he says. You'll probably find that even though your spouse is sick, he or she is worried about you and your relationship as well; being mutually supportive will help you pull through.