Why do I have to deal with these childish behaviors of my spouse at 65?

You choose. Starting point: wrong question-you chose this person, the responsibility for your reaction to what you're dealing with is yours, not your spouse's. Next point: what are you calling childish, and what about it bothers you? Could it be projection (disowning of shadow) or judgement rather than fact? Next point: what do you want, why do you want it? Next point: how do you communicate about it?