In The Washington Post, Rodney Brooks explains the need to have a plan to keep out of your spouse's way. That won't be easy until you can create a routine which engrosses you.
Usually that involves adding something new to your life. A compelling hobby, returning to school or volunteer work could do it.
Often what happens is that those retiring have the fantasy of playing all the golf they want or simply relaxing. That gets old fast. Consequently they turn to their spouse for stimulation. And the spouse pushes back with a demand for a divorce. That is one reason why the divorce rate is so high among Baby Boomers.