It puts a trust issue out there on the couple. However, if both parties are mature and if one or both come in with significant assets, it is necessary to protect yourself and your kids (if it is a second marriage) should things go awry.

I've seen many issues with later-in-life marriages where couples didn't protect their heirs. I would never, ever, considering marrying without a prenup at my age. If the new potential spouse doesn't want it, well, that's a huge red flag.