You sound like you are your spouse were quite cooperative and not particularly dysfunctional, which allowed you to do it this way.

However, for those couples who don't enjoy the sort of cooperative behaviors that you did, they need to, legally, ensure that things are right. That might mean getting counsel immediately, and to draw up a separation arrangement and file it with the court. This oftentimes is a matter of survival, especially with respect to financial and any custodial arrangements.

Many people simply cannot rely on the good will of spouse to honor a written, not legally binding agreement when there is no goodwill left. Assets must be protected and goodwill gestures might fall short on that.

It is good that you were able to work it out in the way you described.