There are several aspects.
1) does her benefit rise to 50% of my check when I start at 70?
No, spousal benefits stops at the higher earner's full retirement age. The accumulation from full retirement age to higher, say 70, will not apply.
"Auxiliary benefits, including both spousal and survivor benefits, are also reduced if they are claimed early, but different rules apply. At the FRA, a spouse is eligible to receive 50 percent of a retired-worker's benefit. Spousal retirement benefits can start at age 62 and are reduced for each month they are claimed before the FRA by slightly different reduction factors than those described earlier.4 However, spousal benefits do not increase if the retired worker earns DRCs.5"
2) Depending at which age you suspend your payment, if you mean suspending after full retirement age, your wife's spousal benefit will suspend, as well.
"Under the new law, you can still voluntarily suspend benefit payments at your full retirement age (currently 66) in order to earn higher benefits for delaying. But during a voluntary suspension, other benefits payable on your record, such as benefits to your spouse, are also suspended."
Please feel free to follow up.
Fiona Chen, MPA, Ph.D., CPA, ABV, CFF, CITP