For the first, do we say, "She didn't used to be my trusted associate" ("used" with the "d") or "She didn't use to be my trusted associate" ("use" with no "d")? And for the second, do we say, "The couple didn't used to swim in the community pool" or "The couple didn't use to swim in the community pool"? And for the second, do we say, "Did the couple used to swim in the community pool?" The correct usage for negative "used to" statements is therefore this: "She didn't use to be my trusted associate." For negative "used to" constructions, these grammar contrarians prescribe this form instead: "She used not to be my trusted associate."
