Can I do anything to maximize my benefits,
Most likely - there is nothing you may do... But still I suggest to verify if your working record is correct on your SSA account - your benefits are calculated based on your working record.
does my disability payments have to convert to retirement payments at age 66
Yes - that is correct. While amount will be the same - benefits will NOT be disability benefits anymore - but will be your regular social security retirement benefits after you reach your FRA - full retirement age which is 66.
and will that change the benefit I have been getting?
No - you will be receiving the same amount.
Also I understand when my wife retires she can get my benefit amount if higher than hers, is that true?
Yes - that is true - your wive is entitled to receive 50% of your benefits if she will start benefits at her full retirement age.
She may receive the larger - social security benefits based on her earning record OR spousal benefits - 50% of your benefits - whatever is higher.