My wife at age 64 can claim her own social security benefit of $689/mo. I do not plan on filing until age 70 in five years and will have a monthly benefit of about $2000. When I file will she be able to claim her spousal benefit, raising her monthly benefit to $1000? ($689+$311 to bring her up to 50% of my benefit).
No, if your wife starts drawing reduced retirement benefits prior to full retirement age, the reduction on her own record is permanent. And, her excess spousal benefit (if any) would be calculated based on 50% of your full retirement age rate (PIA), not your age 70 rate.
For example, say Jane's full retirement age rate (PIA) is $800, but she files at age 64 and receives a reduced rate of $693. When Jane is 69 her husband John, whose PIA is $2000, files for his benefits at age 70 and gets $2640. Jane would then become eligible for an excess spousal benefit of $200 (i.e. 50% of John's PIA minus her own PIA). This benefit would then be added to her reduced retirement benefit to give Jane a combined benefit rate of $893.
You and your wife may want to strongly consider running the maximization software available on this website in order to make sure that you choose the best possible filing strategy.