Accepting an apology doesn’t require “It’s fine.” “Thanks for saying that” works too.

You are allowed to receive an apology without pretending it did not matter. Insisting everything is fine is the socially easy move and it quietly erases the thing you were hurt by, which leaves you resentful and them unsure what happened. There are other honest responses. Acknowledging the effort it took them to say it is one, and it claims nothing about being over it.

Pick a sentence you can say truthfully when somebody apologises to you. I know that was hard to say works, and so does I need a bit of time. Then let the rest arrive at its own speed instead of being performed on the spot.