A majority of older U.S. adults, including 91% of those with more than $250,000 in investable assets, do not have a prenuptial agreement, but they would if they had to do it over again, according to a survey conducted by the Harris Poll on behalf of TD Ameritrade.

Meanwhile, the survey of 2,000 adults age 40 to 79 with at least $25,000 in investable assets found that, while confident they can manage in the event of a divorce or the death of a spouse later in life, 40% of Americans do not have a financial plan.

Men, the survey found, are more unprepared than women (45% versus 36%).

Keith Denerstein, director of investment products and guidance at TD Ameritrade, said planning finances around the potential end of a relationship due to divorce or death can be uncomfortable, but “while the trepidation is understandable, preparing for these possible scenarios is important for future financial security, and therefore should be a key part of financial planning,” he said.

As for divorcees, 40% agreed that getting divorced threw their retirement plans off course (46% of men versus 36% of women). One-third of divorcees delayed their divorce longer than they wanted to due to financial concerns.

And while most divorcees (97%) did not have a pre-nup in their previous marriage, 42% said they would get one if they remarried. The percentage rises to 70% among those with more $250,000 in investable assets.

Seventy-five percent said the agreement should include retirement assets.

The survey also indicated many Americans, regardless of relationship status, are not sure how to approach end-of-life planning with their families. This is especially true for those in their 40s and 50s, the report said, with more than half unsure how to structure their inheritance.

Additionally, the survey found that only one in three have shared financial passwords in case of an emergency; 40% have discussed desired arrangements for their funeral with family; only 30% have set aside money for end-of-life care; only 28% have created an emergency plan in case something happens to the household's primary financial decision maker; only 20% have told their children how to access and manage their assets in case of an emergency; only 20% have discussed inheritance and legacy planning with their children; and only 19% have discussed health and caretaking planning with children.