Legal Question in Family Law in California

For a 31 year marriage, spousal support would essentially be indefinite. Fifteen years minimum. Of course at your age and his, the courts will take into account his right to retire at some point and reduce his support payments at that time, and support is always limited and controlled by the specific family economic circumstances, but generally for a marriage of that length support would be open ended, with his right to ask for reduction or termination in the future only for good cause related to his economic circumstances.