In some instances, caregiving's toll on the relationship may simply be too high. "There may come a time when your spouse comes to you and says, 'I can't do this anymore,'" O'Dell explains. "If that's the case, you have to respect your partner's feelings."

Your spouse may not verbalize distress, says O'Dell. "He or she may come home later and later every night, or overeat, or drink too much. You need to pay attention, and you need to take it seriously."

That's why experts say it's essential that couples to go into the caregiving situation with their eyes wide open and have a few backup plans in place -- possible alternative living arrangements for the senior, for example -- in case things don't work out.

• Explore alternatives by researching senior facilities in your area, and take the time to visit one or two that sound appropriate.
• Find out if any of your siblings or other relatives would be able and willing to accommodate the senior, either for short stays or as a permanent alternative.
• Make it clear to your siblings that while you're willing to care for your aging relative, you're not willing to sacrifice your marriage to do so. This means that you may need their support for both day-to-day care and to help you make alternative arrangements if it doesn't work out.

In some cases, a change in the caregiving arrangements may ease the situation -- but, says O'Dell, the bottom line is that your marriage comes first. "In the end," she states, "I don't recommend that people place caregiving above their marriage."

Has caregiving affected your relationship with your spouse or significant other? Tell your story here.