My husband started drawing his SS at age 62 back in 2005. I will turn 67 in May 2019 and have been a high wage earner. Is it possible to apply for spousal benefits on his reduced SS at my FRA and delay taking my benefit until age 70?
Yes, you can and probably should file for spousal benefits as soon as possible. It sounds like you could have been drawing the spousal benefits since the month you reached your full retirement age (FRA) of 66, but now you can only claim those benefits retroactively for a maximum of 6 months. As long as you file only for spousal benefits, your Social Security retirement benefit rate will continue to grow until you reach age 70.
By the way, the reason that you can file for just spousal benefits without filing for your own benefits is because you were born prior to January 2 1954. People born after January 1 1954 no longer have that option (https://www.ssa.gov/planners/retire/deemedfaq.html).