Anonymous wrote:OP here.
I suppose one of the biggest concerns is that he will start to grow older much sooner and I would and the relationship dynamic may quickly change. Of course, this could happen with any relationship - sickness and accidents are always a possibility, but in this case - the change is almost a certainty. Does anyone have first hand experience with something like this? Would this be too risky and just not worth it? Kids are not an issue, not planning on kids.
Of course sometimes one loses a partner suddenly and of course the odds are higher that the older one will go first. But I've watched couples where the one partner is 10-15 years older than the other and gets old or sick. The younger partner gives up freedom and sleep. They manage complicated medical finances and in some cases, in-house or residential care. The relationship changes, they make difficult decisions, it's lonely and their patience is tested. It's called "the long goodbye." In some ways a 20 year gap would be easier because the younger partner would be more energetic and more mentally fit to step up. But they might be doing it for their parents simultaneously...
A beautiful memoir written by a woman whose older (less than 20 years though) husband (they are childless) has a stroke is One Hundred Names for Love: A Stroke, a Marriage, and the Language of Healing by Diane Ackerman. You really get a feel for their relationship dynamic at that stage of life.