I am now 68 and have not filed for SS benefits and continue to work - waiting until age 70. My wife of 40 + years turns 66 this summer (2017). My benefit amount will likely be at the SS maximum. Although she has retirement credits from working at various times over the years, 50% of my benefit, as a spousal benefit, will be substantially higher than hers. Are we better off waiting until I turn 70 for her to draw a benefit, or is her spousal benefit capped when she turns 66 and reaches FRA? The goal is to receive the maximum benefit for both of us.
Your wife can't receive spousal benefits until you start drawing your benefits. The rate she would be eligible for is based on 50% of your full retirement age rate (PIA), not your age 70 rate that includes delayed retirement credits.
It sounds like the best strategy for your goals would be for your wife to file for retirement benefits on her own record at age 66, and for you to file for spousal benefits only on her record at that time. You can then switch to your own record at age 70, and your wife can file for an excess spousal benefit on your record at that time. This is only an educated guess based on the information furnished in your question, so you should likely consider running the maximization software available on this website in order to make sure that you choose the best strategy.