Robertson was asked what advice a man should give to a friend who began seeing another woman after his wife started suffering from the incurable neurological disorder.
Robertson said, "I know it sounds cruel, but if he's going to do something, he should divorce her and start all over again, but make sure she has custodial care and somebody looking after her."
The chairman of the Christian Broadcasting Network, which airs the "700 Club," said he wouldn't "put a guilt trip" on anyone who divorces a spouse who suffers from the illness, but added, "Get some ethicist besides me to give you the answer."
Most Christian denominations at least discourage divorce, citing Jesus's words in the Gospel of Mark that equate divorce and remarriage with adultery.
Terry Meeuwsen, Robertson's co-host, asked him about couples' marriage vows to take care of each other "for better or for worse" and "in sickness and in health."
"If you respect that vow, you say 'til death do us part,'" Robertson said during the Tuesday broadcast. "This is a kind of death."
The Associated Press contributed to this report.