Many Americans say caring for a frail spouse is more stressful that caring for a parent or in-law.
In an AP-N-O-R-C poll, the average age of spouse caregivers was 67, compared with 58 for people who've cared for a parent.
And spouse caregivers were most likely to report stress.
They also say that caregiving weakened their relationship with the partner and burdened their finances.